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Akio Goto

Section

Center for Northeast Asian Studies

Job title

Assistant Professor

Degree

博士（理学）（北海道大学）
修士（理学）（北海道大学）

researchmap

https://researchmap.jp/read0191598

J-GLOBAL ID

200901039820745770

Professional Memberships 3

日本地球惑星科学連合
日本鉱物科学会
日本火山学会

Research Interests 6

air wave
Zao volcano
explosion
volcano
rheology
magma

Research Areas 1

Natural sciences / Solid earth science / Volcanology

Papers 67

In situ observation of glass-like fragmentation of high-temperature silicate melts generating fine ashes Peer-reviewed

Atsuko Namiki, Satoshi Okumura, Akio Goto, Tsutomu Yamada

Communications Earth & Environment　2023/05/05

DOI： 10.1038/s43247-023-00816-3 　
Geological constraints on volcanic-fluid pathways at the Maruyamasawa-Fumarolic-Geothermal-Area, and its relation to the present magmatic-hydrothermal activity in Zao Volcano, Tohoku, Japan Peer-reviewed

Takumi Imura, Masao Ban, Kae Tsunematsu, Akio Goto, Jun Okada, Miwa Kuri

Journal of Volcanology and Geothermal Research　437　107793-107793　2023/05
Publisher: Elsevier BV
DOI： 10.1016/j.jvolgeores.2023.107793 　

ISSN： 0377-0273
Molecular-scale structural changes of silicate melts under tension revealed by time-resolved X-ray diffraction Peer-reviewed

Satoshi Okumura, Kentaro Uesugi, Akio Goto, Atsuko Namiki, Kazuhisa Matsumoto, Tatsuya Sakamaki

Chemical Geology　621　121372-121372　2023/03
Publisher: Elsevier {BV}
DOI： 10.1016/j.chemgeo.2023.121372 　

ISSN： 0009-2541
Water Cycles and Geothermal Processes in a Volcanic Crater Lake Peer-reviewed

Kazuhisa A. Chikita, Akio Goto, Jun Okada, Takashi Yamaguchi, Hideo Oyagi

Hydrology　10　(3)　54-76　2023/02/22
Publisher: MDPI AG
DOI： 10.3390/hydrology10030054 　

eISSN： 2306-5338

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Exploring how the hydrological and thermal conditions of a volcanic lake change in response to volcanic activity is important to identify the signs of a volcanic eruption. A water cycle system and a geothermal process in a crater lake, Okama, in the active Zao Volcano, Japan, were explored by estimating the hydrological and chemical budgets of the lake, and analyzing the time series of lake water temperature, respectively. In 2021, the lake level consistently increased by snowmelt plus rainfall in May–June, and then stayed nearly constant in the rainfall season of July–September. The hydrological budget estimated during the increasing lake level indicated that the net groundwater inflow is at any time positive. This suggests that the groundwater inflow to the lake is controlled by the water percolation into volcanic debris from the melting of snow that remained in the catchment. Solving the simultaneous equation from the hydrological and chemical budgets evaluated the groundwater inflow, Gin, at 0.012–0.040 m3/s, and the groundwater outflow, Gout, at 0.012–0.027 m3/s in May–September 2021. By adding the 2020 values of Gin and Gout evaluated at the relatively high lake level, it was found that Gin and Gout exhibit highly negative and positive correlations (R2 = 0.661 and 0.848; p < 0.01) with the lake level, respectively. In the completely ice-covered season of 15 December 2021–28 February 2022, the lake water temperature increased between the bottom and 15 m above the bottom at the deepest point, which reflects the geothermal heat input at the bottom. The heat storage change during the increasing water temperature was evaluated at a range of −0.4–5.5 W/m2 as the 10-day moving average heat flux. By accumulating the daily heat storage change for the calculated period, the water temperature averaged over the heated layer increased from 1.08 to 1.56 °C. The small temperature increase reflects a stagnant state of volcanic activity in the Zao Volcano. The present study could be useful to investigate how an active volcano responds to water percolation and geothermal heat.
Rheology of nanocrystal-bearing andesite magma and its roles in explosive volcanism Peer-reviewed

Satoshi Okumura, Kentaro Uesugi, Akio Goto, Tatsuya Sakamaki, Kazuhisa Matsumoto, Akihisa Takeuchi, Akira Miyake

COMMUNICATIONS EARTH & ENVIRONMENT　3　(1)　2022/10
Publisher: SPRINGERNATURE
DOI： 10.1038/s43247-022-00573-9 　

eISSN： 2662-4435

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Recent petrological and experimental studies have proposed that explosive volcanism may originate from the formation of nanoscale crystals in magma and the resultant ductile-brittle transition. However, the rheology of magma with quantified volume fractions of nanoscale crystals has not been investigated before, and thus, the formation of nanoscale crystals causing magma fragmentation that explains the origin of explosive eruptions is not conclusive. Here, we investigate the rheology of andesite magma with nanoscale crystals (magnetite). For this, a glass fibre elongation experimental apparatus with a heating furnace was developed at the synchrotron radiation X-ray system (SPring-8). During melt elongation, we observed the formation of crystals using small-angle X-ray scattering and wide-angle X-ray diffraction. Our experimental data demonstrate that magma viscosity increases with the formation of nanoscale crystals, but the degree of the increase is much lower than that predicted from analogue materials. Finally, we conclude that nanocrystal formation in intermediate composition magmas cannot explain rheological transition and other mechanisms such as nanocrystal agglomeration (not observed in our experiments) and/or heterogeneous nucleation of gas bubbles on nanocrystals are required to induce mafic to intermediate explosive volcanisms.Nanolite crystallisation increases bulk viscosity in mafic to intermediate magmas but other mechanisms are required to promote explosive eruptions, according to an experimental study using natural samples.
Hydrological and Chemical Budgets of Okama Crater Lake in Active Zao Volcano, Japan Peer-reviewed

Kazuhisa A. Chikita, Akio Goto, Jun Okada, Takashi Yamaguchi, Satoshi Miura, Mare Yamamoto

Hydrology　9　(2)　2022/02

DOI： 10.3390/hydrology9020028 　

eISSN： 2306-5338

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The Okama Crater Lake is located in the highly active Zao Volcano on the boundary of Miyagi and Yamagata Prefectures, Japan. At present, the lake stays relatively calm with neither bubbling, steaming nor gas smell at a pH of 3.2–3.4, though the lake did change color with steaming from the water surface in 1939 as the result of one of Zao’s volcanic activities. In order to clarify the geothermal effect on Okama and the groundwater flow system below or around Okama, field observations were performed in 2019 and 2020. Groundwater inflow and outflow in Okama were separately evaluated by estimating the hydrological and chemical budgets of the lake, based on the hydrometeorology, water temperature and river inflow measured in the field. The average groundwater inflow and outflow were estimated at 0.012 m3 /s and 0.039 m3 /s during the non-rainfall periods of 2020, respectively. A surplus of groundwater outflow makes the lake level consistently decrease during non-rainfall periods or the completely ice-covered season. In the completely ice-covered periods, the water temperature consistently increased at 0–15 m above the lake bottom, which is probably due to thermal leakage from a hydrothermal reservoir below the lake bottom. The heat fluxes averaged over December 2019–April 2020 and December 2020–March 2021 were calculated at 2.5 and 2.9 W/m2, respectively. A coupling between the estimated groundwater inflow and the calculated geothermal heat flux was used to evaluate the temperature of inflowing groundwater.
Reply to: Hiroaki Sato, Shigeru Suto, Tadahide Ui, Toshitsugu Fujii, Takahiro Yamamoto, Shinji Takarada, Keiichi Sakaguchi, “Flowage of the 1991 Unzen lava; discussion to Goto et al. ‘Rigid migration of Unzen lava rather than flow’, J. Volcanol. Geotherm. Res, 110, 107073.” Peer-reviewed

Akio Goto, Keiichi Fukui, Takehiko Hiraga, Yasunori Nishida, Hidemi Ishibashi, Takeshi Matsushima, Tsuyoshi Miyamoto, Osamu Sasaki

Journal of Volcanology and Geothermal Research　107384-107384　2021/09
Publisher: Elsevier BV
DOI： 10.1016/j.jvolgeores.2021.107384 　

ISSN： 0377-0273
Rigid migration of Unzen lava rather than flow Peer-reviewed

Akio Goto, Keiichi Fukui, Takehiko Hiraga, Yasunori Nishida, Hidemi Ishibashi, Takeshi Matsushima, Tsuyoshi Miyamoto, Osamu Sasaki

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH　407　2020/12
Publisher: ELSEVIER
DOI： 10.1016/j.jvolgeores.2020.107073 　

ISSN： 0377-0273

eISSN： 1872-6097

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We have reassessed the mode of advance of lava erupted in the 1990s from Unzen Fugen-dake Volcano in northwestern Kyushu, Japan. The apparent viscosity of Unzen lava had been estimated to be 0.9-4.2 x 10(10) Pa s from the observed lava surface velocity in 1991, using Jeffreys model, based on the assumption that the lava was a Newtonian or Bingham fluid. In contrast, the viscosity of synthetic groundmass glass derived from Unzen lava had been measured in the laboratory at expected lava temperatures (780 degrees C-880 degrees C) to be 10(11)-10(13) Pa s, considerably higher than the viscosity based on field observation. If the suspension effect of crystals is taken into consideration for groundmass glass, several orders of magnitude higher viscosity than observed should be expected for Unzen lava. To seek the source of the disparity in viscosity estimates, we first performed uniaxial-compression viscometry on natural Unzen lava samples collected in 1991 and thereby confirmed that the lava viscosity was actually higher than determined by field observations and equal to or higher than the fluid-solid threshold viscosity (10(12) Pas). This suggests that the observational viscosity had been underestimated. From reanalysis of the lava migration using video and photographs, contemporaneous with the field-based viscosity estimation, we found that the lava behavior was far from that of a fluid. Apparently, the lava lobe lost its fluidity at the flow front and instead advanced rigidly, thereby indicating that the application of Jeffreys model had incorrectly led us to underestimate viscosity. Although we used only the 1991 lava samples and image data, we infer that rigid migration was common for all exogenous lava lobes during the 1991-1995 activity. Our comparative study demonstrates that cooled and/or degassed lavas could show higher mobility than expected from experimentor model-based viscosity. Apparently this occurs when the frictional force is smaller between lobe base and underlying slope than the viscous resistance inherent in lava. (C) 2020 Elsevier B.V. All rights reserved.
An experimental system for time-resolved x-ray diffraction of deforming silicate melt at high temperature Peer-reviewed

Satoshi Okumura, Kentaro Uesugi, Tatsuya Sakamaki, Akio Goto, Masayuki Uesugi, Akihisa Takeuchi

REVIEW OF SCIENTIFIC INSTRUMENTS　91　(9)　2020/09
Publisher: AMER INST PHYSICS
DOI： 10.1063/5.0009769 　

ISSN： 0034-6748

eISSN： 1089-7623

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Rheological behavior of silicate melts controls the dynamics of volcanic eruptions. Previous experimental studies have investigated melt viscosity and found non-Newtonian behavior of the melt under a high shear rate. However, the relationship between macroscopic rheology and atomic-scale behavior under shear remains unclear. We developed an experimental system for time-resolved x-ray diffraction (XRD) at high temperature to investigate the atomic-scale structural change in melts under shear. The manufactured deformation apparatus and heating furnace were set on the synchrotron radiation x-ray beamline (BL20XU) of SPring-8; the XRD pattern of the melt at high temperature could be observed using this system because the furnace mainly consists of a boron nitride cylinder with high x-ray transmittance. Here, we report results of fiber elongation experiments for a soda-lime melt. Melt fibers with similar to 0.7 mm in diameter and similar to 27 mm long were elongated at 100 mu m sec(-1) at temperatures of 595 degrees C and 620 degrees C, and the XRD pattern was obtained every 100 msec. Brittle failure of the melt occurred at 595 degrees C, whereas the melt viscously elongated at 620 degrees C. The XRD patterns obtained during elongation did not indicate any clear change immediately before brittle failure. The intensity of the XRD pattern decreased with the elongation at 620 degrees C, although there was no clear variation in its shape. These results indicate that the atomic-scale structure observed by XRD may not change during the elastic and viscous elongation of the soda-lime melt. This experimental system will be further developed and applied to more polymerized and natural silicate melts.
Prediction of Eruption Courses in Volcanoes Without Eruptions Under Modern Observation System: Example of Zao Volcano Peer-reviewed

伴雅雄, 及川輝樹, 山崎誠子, 後藤章夫, 山本希, 三浦哲

火山　64　(2)　131‐138(J‐STAGE)　2019

DOI： 10.18940/kazan.64.2_131 　

ISSN： 0453-4360
Decrease of iodine isotopic ratio observed in crater lake and geothermal area at Zao volcano

T. Matsunaka, K. Sasa, K. Sueki, T. Takahashi, M. Matsumura, A. Goto, T. Watanabe, N. Tsuchiya, N. Hirano, M. Kuri, M. Takahashi, K. Kazahaya, I. Miyagi, H. Matsuzaki

UTTAC ANNUAL REPORT 2015　20-21　2016
Changes in iodine isotopic ratio of crater lake and volcanic activity at Zao volcano, Japan Peer-reviewed

松中哲也, 笹公和, 末木啓介, 高橋努, 松村万寿美, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 松崎浩之

KEK Proceedings (Web)　(2015-4)　55-61 (WEB ONLY)　2015/11
P83 Rheology of Unzen Fugen-dake Heisei lava

Goto A.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2015　181-181　2015
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2015.0_181 　
Changes in ¹²⁹I/¹²⁷I ratio of crater lake and volcanic activity at Zao volcano

Matsunaka, T, Sasa, K, Sueki, K, Takahashi, T, Matsumura, M, Goto, A, Watanabe, T, Tsuchiya, N, Hirano, N, Matsuzaki, H

UTTAC ANNUAL REPORT 2014　2015
Wideband acoustic records of explosive volcanic eruptions at Stromboli: New insights on the explosive process and the acoustic source Peer-reviewed

A. Goto, M. Ripepe, G. Lacanna

GEOPHYSICAL RESEARCH LETTERS　41　(11)　3851-3857　2014/06
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1002/2014GL060143 　

ISSN： 0094-8276

eISSN： 1944-8007

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Wideband acoustic waves, both inaudible infrasound (< 20 Hz) and audible component (> 20 Hz), generated by strombolian eruptions were recorded at 5 kHz and correlated with video images. The high sample rate revealed that in addition to the known initial infrasound, the acoustic signal includes an energetic high-frequency (typically > 100 Hz) coda. This audible signal starts before the positive infrasound onset goes negative. We suggest that the infrasonic onset is due to magma doming at the free surface, whereas the immediate high-frequency signal reflects the following explosive discharge flow. During strong gas-rich eruptions, positively skewed shockwave-like components with sharp compression and gradual depression appeared. We suggest that successive bursting of overpressurized small bubbles and the resultant volcanic jets sustain the highly gas-rich explosions and emit the audible sound. When the jet is supersonic, microexplosions of ambient air entrained in the hot jet emit the skewed waveforms.
Study on monitoring of volcanic activity using ¹²⁹I/¹²⁷I ratios in crater lake and hot spring at Zao volcano, Miyagi Prefecture

Matsunaka, T, Sasa, K, Sueki, K, Shibayama, N, Takahashi, T, Matsumura, M, Satou, Y, Matsuzaki, H, Goto, A, Watanabe, T, Tsuchiya, N, Hirano, N, Kizaki, A

UTTAC ANNUAL REPORT 2013　29-30　2014
無人火山探査車MOVEの開発とその運用課題 Peer-reviewed

後藤章夫, 谷口宏充, 市原美恵

日本惑星科学会誌　21　(2)　103-110　2012/06
Publisher: The Japanese Society for Planetary Sciences
DOI： 10.14909/yuseijin.21.2_103 　

ISSN： 0918-273X
Monotonic infrasound and Helmholtz resonance at Volcan Villarrica (Chile) Peer-reviewed

A. Goto, J. B. Johnson

GEOPHYSICAL RESEARCH LETTERS　38　(6)　2011/03
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2011GL046858 　

ISSN： 0094-8276

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Monotonic infrasound with stable peaked frequency of 0.77 Hz was recorded at Volcan Villarrica in January 2010. Similar monotonic infrasound had been previously reported at Villarrica (e. g., Ripepe et al. [2010]). Using joint infrasound and visual observations from a suspended camera we demonstrate that the likely source of infrasound is Helmholtz resonance produced from a cavity with volume 10(5) m(3) that separates the active convecting lava lake from an overhanging spatter roof. Spatter roof dimension (65 m diameter) and vent diameter (10 m) in the roof are constrained from video observations. Assuming a cylindrical cavity we infer a cavity height of 31 m that is corroborated by video records of spatter drips. The drips take as long as 2.2 s to fall from the roof into the lake, corresponding to a height of more than 24 m, which is in good agreement with the observed resonance frequency. Citation: Goto, A., and J. B. Johnson (2011), Monotonic infrasound and Helmholtz resonance at Volcan Villarrica (Chile), Geophys. Res. Lett., 38, L06301, doi: 10.1029/2011GL046858.
P34 Spectral analysis of eruption acoustics recorded on Stromboli volcano

Goto Akio, Ripepe Maurizio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2011　146-146　2011
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2011.0_146 　
Simulations of measures to control lava flows Peer-reviewed

Eisuke Fujita, Masataka Hidaka, Akio Goto, Susumu Umino

BULLETIN OF VOLCANOLOGY　71　(4)　401-408　2009/05
Publisher: SPRINGER
DOI： 10.1007/s00445-008-0229-7 　

ISSN： 0258-8900

eISSN： 1432-0819

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We evaluated the quantitative effects of artificial barriers, water-cooling and guiding channels on lava flow using the lava simulation program LavaSIM. Lava flow is basically subject to the topography around the path, effusive rate and viscosity. To prevent damage due to lava flow, we conducted experiments in controlling the flow direction, velocity and temperature. The simulation demonstrated that artificial barriers can successfully change the direction of a lava flow and is more effective when placed nearly parallel to the flow direction at a point where the topography is not very steep, while a barrier placed perpendicular to the flow direction can only stop the flux temporarily, ultimately allowing the solidified crust to accumulate and causing the following mass to go over the barrier. The water-cooling trial was also effective in controlling the direction and temperature, although the amount of water was as much order as 10(5) m(3). The guiding channels successfully control the direction and inundated area but only in local areas.
Re‐examination of viscosity evaluation model by Goto (1997) Peer-reviewed

後藤章夫

北海道大学地球物理学研究報告　72　(72)　159-175　2009/03/15
Publisher:
DOI： 10.14943/gbhu.72.159 　

ISSN： 0439-3503
Airwaves generated by an underwater explosion: Implications for volcanic infrasound Peer-reviewed

M. Ichihara, M. Ripepe, A. Goto, H. Oshima, H. Aoyama, M. Iguchi, K. Tanaka, H. Taniguchi

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH　114　(B3)　2009/03
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2008JB005792 　

ISSN： 2169-9313

eISSN： 2169-9356

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A shallow explosion in a fluid is one of the fundamental processes of airwave generation in volcanic eruptions. To better understand the mechanism of the airwave generation, underwater explosion experiments were conducted. Although the underwater explosions have been intensely studied over the last century, airwaves have received little attention. In this study, pressure waves were measured in air and under water, and the corresponding motion of the water surface was captured by a high-speed video camera. Airwaves and associated styles of the surface motion show similarities determined by the scaled depth, defined as the depth divided by the cubic root of the explosion energy. The air waveforms are quite different from the pressure waves measured in the water and cannot be completely explained by linear transmission of pressure waves from water to air. The mechanism of airwave generation is a combination of wave transmission and dynamics of the interface boundary. The first mechanism directly reflects the explosion source, and the same source is also observed as the underwater pressure waves. On the other hand, the second is not necessarily visible in the underwater pressure waves but will provide information on the mechanical properties and behavior of the material above the explosion source. Each mechanism is analyzed in the experiments.
火山探査移動観測ステーションMOVEの開発

谷口宏充, 後藤章夫, 市原美恵

ロボット　187　10-16　2009/03
Airwaves generated by an underwater explosion: Implications for volcanic infrasound Peer-reviewed

M. Ichihara, M. Ripepe, A. Goto, H. Oshima, H. Aoyama, M. Iguchi, K. Tanaka, H. Taniguchi

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH　114　(3)　2009/03
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2008JB005792 　

ISSN： 2169-9313

eISSN： 2169-9356

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A shallow explosion in a fluid is one of the fundamental processes of airwave generation in volcanic eruptions. To better understand the mechanism of the airwave generation, underwater explosion experiments were conducted. Although the underwater explosions have been intensely studied over the last century, airwaves have received little attention. In this study, pressure waves were measured in air and under water, and the corresponding motion of the water surface was captured by a high-speed video camera. Airwaves and associated styles of the surface motion show similarities determined by the scaled depth, defined as the depth divided by the cubic root of the explosion energy. The air waveforms are quite different from the pressure waves measured in the water and cannot be completely explained by linear transmission of pressure waves from water to air. The mechanism of airwave generation is a combination of wave transmission and dynamics of the interface boundary. The first mechanism directly reflects the explosion source, and the same source is also observed as the underwater pressure waves. On the other hand, the second is not necessarily visible in the underwater pressure waves but will provide information on the mechanical properties and behavior of the material above the explosion source. Each mechanism is analyzed in the experiments.
B46 Surface morphology and groundmass texture of the 1951 lava flow, Izu-Oshima volcano

Oguri Naoki, Miyamoto Tsuyoshi, Goto Akio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2009　96-96　2009
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2009.0_96 　
Airwaves generated by an underwater explosion: Implications for volcanic infrasound Peer-reviewed

M. Ichihara, M. Ripepe, A. Goto, H. Oshima, H. Aoyama, M. Iguchi, K. Tanaka, H. Taniguchi

Journal of Geophysical Research　114　(B3)　B03210　2009

DOI： 10.1029/2008JB005792 　

ISSN： 0148-0227
B18 Analysis of video images and high rate sampled acoustic waves on Stromboli volcano

Goto Akio, Ripepe Maurizio, Lacanna Giorgio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2008　70-70　2008
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2008.0_70 　
放熱率測定に基づいた有珠2000年噴火の活動推移長期予測 Peer-reviewed

後藤章夫, 鍵山恒臣, 宮本毅, 横尾亮彦, 谷口宏充

北海道大学地球物理学研究報告　70　(70)　137-144　2007/03/15
Publisher:
DOI： 10.14943/gbhu.70.137 　

ISSN： 0439-3503
Long-term prediction of Usu volcano 2000 eruptive activity based on the measurements of heat discharge rate

Akio Goto, Tsuneomi Kagiyama, Tsuyoshi Miyamoto, Akihiko Yokoo, Hiromitsu Taniguchi

Journal of the Hokkaido University, Faculty of Science, Series VII: Geophysics　(70)　137-144　2007

ISSN： 0441-067X

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The energy source of volcanic activity is the heat of magma. Heat discharge rate on the initial stage of Usu 2000 eruptive activity was estimated to be around 1×109 J/sec, that was over one order higher than that on the initial stage of the 1977 activity, and comparable to its peak release rate observed after two years from the beginning of the eruptive activity. Compare to the 1977 activity, much shorter duration of the 2000 activity may be the result of rapid cooling of the intruded magma. Abundant ground water supplied from Lake Toya might remove the heat effectively through active vapor plume rise.
P10 Near-field observation of air wave and explosion column on Semeru volcano : their relationship and the similarity with experimental results

Goto A., Iguchi M., Furukawa T., Ogawa T., Sasoh A., Taniguchi H., Obayashi S.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2007　40-40　2007
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2007.0_40 　
Atmospheric pressure waves in the field of volcanology Peer-reviewed

Akihiko Yokoo, Mie Ichihara, Akio Goto, Hiromitsu Taniguchi

SHOCK WAVES　15　(5)　295-300　2006/09
Publisher: SPRINGER
DOI： 10.1007/s00193-006-0009-2 　

ISSN： 0938-1287

eISSN： 1432-2153

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Atmospheric pressure waves are a notable phenomenon associated with explosive volcanic eruptions. They can provide us with information about eruption processes that are useful both scientifically and practically. In this paper, we give a brief review of studies that have been carried out on this phenomenon in the field of volcanology. Then, we introduce a prototype tool called 'MOVE' (Mobile Observatory for Volcanic Explosions). It is a remote-controlled vehicle carrying various instruments to observe pressure waves and the eruption processes.
P100 Analogue experiments of volcanic explosions using high pressure gas : part 4: pressure wave(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2006 FALL MEETING)

Goto A., Furukawa T., Ogawa T., Sasoh A., Taniguchi H., Ohbayashi S.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2006　214-214　2006
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2006.0_214 　
P48 Lavaflow simulation for the 2001 Etna eruption by LavaSIM(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2006 FALL MEETING)

Proietti Cristina, Marcella Maria, Coltelli Mauro, Umino Susumu, Goto Akio, Fujita Eisuke

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2006　162-162　2006
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2006.0_162 　
水中爆発実験2001～2005の結果報告

市原美恵, 後藤章夫, 谷口宏充, 大島弘光, 井口正人

火山爆発のダイナミックス平成17年度研究成果報告書 , pp. 273-278　2006
VTFS project: Development of the lava flow simulation code LavaSIM with a model for three-dimensional convection, spreading, and solidification Peer-reviewed

M Hidaka, A Goto, S Umino, E Fujita

GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS　6　(7)　2005/07
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2004GC000869 　

ISSN： 1525-2027

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The lava flow simulation code LavaSIM has been developed to give accurate predictions of volcanic disasters and to support evacuation plans. The code uses three- dimensional analysis with free surface evaluation, including boundary transport between the melt and the crust. It is therefore applicable to various types of lava flows and flow behaviors such as flood basalts, subaqueous lava flows, and levee formation. Heat transfer between the lava and the ground, air, and water, and between the melt and crust of the flow is calculated by using appropriate relations. The code has been verified by applying it to actual lava flows, and the simulation results have been compared with observations of the Izu- Osima flows of 1986. The lava flow rate, temperature, and properties were assigned values based on data from existing literature. The comparisons demonstrated the code's capability for prediction of inundated areas and maximum flow lengths. The present code is expected to be useful for real- time prediction during eruptions, in addition to assessing volcanic hazards and designing protection structures for existing installations against possible future lava flows.
Viscosity measurements of hydrous rhyolitic melts using the fiber elongation method Peer-reviewed

A Goto, H Taniguchi, A Kitakaze

BULLETIN OF VOLCANOLOGY　67　(6)　590-596　2005/07
Publisher: SPRINGER
DOI： 10.1007/s00445-004-0401-7 　

ISSN： 0258-8900

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We have devised a new, simple and easy technique to measure the viscosity of hydrous silicate melts by combining an autoclave for melt hydration and the fiber elongation method for viscosity measurement. Using this, we measured the viscosity of hydrous rhyolitic melts whose water content ranges from 0.02 to 0.58 wt%. We observed a drastic decrease in viscosity against water content: 0.1 wt% water decreases the viscosity about an order of magnitude. Even when the water content is only 0.02 wt%, the viscosity decreased about half an order of magnitude. These results clearly demonstrate that the effect of water on viscosity should not be ignored even when it occurs as a trace constituent. We compared our experimental data with those derived from a non-Arrhenian viscosity model, which is considered to be applicable to calc-alkaline samples. This model succeeded in expressing the viscosity variation against water content but was unable to accurately predict the measured viscosity of liquids.
P49 Analogue experiments of volcanic explosions using high pressure gas : part 2 : scaling rule(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2005 FALL MEETING)

Goto A., Furukawa T., Ogawa T., Sasoh A., Taniguchi H.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2005　149-149　2005
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2005.0_149 　
Effect of Thermal Memory on Viscosity Increase in Magmatic Silicate Melts at Low Temperature without Crystallization

Akio Goto, Hiromitsu Taniguchi, Yasunori Nishida, Hiromitsu Oshima

Proceedings of 2004 Western Pacific Geophysics Meeting　V33B-93　2004/08
低温での粘性増加に対する熱履歴の影響

後藤章夫, 西田泰典, 大島弘光

北海道大学地球物理学研究報告　(67)　1-10　2004/03/15
Publisher:
DOI： 10.14943/gbhu.67.1 　

ISSN： 0439-3503
Surface morphology of LA lava flow in Izu-Oshima 1986 eruption Peer-reviewed

Shigehiro Kanno, Akio Goto

Northeast Asian Studies　8　(8)　105-126　2004/03
Publisher:
ISSN： 1343-9332
Aeromagnetic Survey at Iwate Volcano

坂中伸也, 田中良和, 宇津木充, 谷口宏光, 後藤章夫

秋田大学工学資源学部研究報告　24　(24)　1-10　2003/10/31
Publisher: Akita University
ISSN： 1345-7241
The effect of "thermal memory" on the viscosity change with time

Goto Akio, Taniguchi Hiromitsu

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2003　84-84　2003
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2003.0_84 　
Energy and depth of Usu 2000 phreatic explosions Peer-reviewed

A Yokoo, H Taniguchi, A Goto, H Oshima

GEOPHYSICAL RESEARCH LETTERS　29　(24)　2195　2002/12
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2002GL015928 　

ISSN： 0094-8276

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[1] On 31 March 2000, the Usu volcano located in Hokkaido, Japan began erupting after 22 years of dormancy. After the first phreato-magmatic explosion, there were many small-scale phreatic explosions at the Nishiyama and Kompirayama Craters. In April and May, observations were made using a piezo blast-sensor and a visible video recorder to get a better understanding of volcanic explosions. The data thus obtained were analyzed using the scaling-laws that relate surface phenomena to both explosion energy and depth. The analysis using the shape of the explosion-cloud and the peak over-pressure of the volcanic blast-wave indicated that the average explosion energy and depth of the phreatic explosions of mid-April ranged from 10(10) to 10(12) J and originated from between just beneath the ground surface to a depth of a few tens of meters.
Energy and depth of Usu 2000 phreatic explosions Peer-reviewed

A Yokoo, H Taniguchi, A Goto, H Oshima

GEOPHYSICAL RESEARCH LETTERS　29　(24)　48-1　2002/12
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2002GL015928 　

ISSN： 0094-8276

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[1] On 31 March 2000, the Usu volcano located in Hokkaido, Japan began erupting after 22 years of dormancy. After the first phreato-magmatic explosion, there were many small-scale phreatic explosions at the Nishiyama and Kompirayama Craters. In April and May, observations were made using a piezo blast-sensor and a visible video recorder to get a better understanding of volcanic explosions. The data thus obtained were analyzed using the scaling-laws that relate surface phenomena to both explosion energy and depth. The analysis using the shape of the explosion-cloud and the peak over-pressure of the volcanic blast-wave indicated that the average explosion energy and depth of the phreatic explosions of mid-April ranged from 10(10) to 10(12) J and originated from between just beneath the ground surface to a depth of a few tens of meters.
野外爆発実験から見た有珠2000年噴火 Peer-reviewed

尾亮彦, 谷口宏充, 大島弘光, 後藤章夫, 大場司, 宮本毅

Bulletin of the Volcanological Society of Japan　47　243-253　2002/09

DOI： 10.18940/kazan.47.4_243 　
Effect of explosion energy and depth on the nature of explosion cloud - A field experimental study Peer-reviewed

T Ohba, H Taniguchi, H Oshima, M Yoshida, A Goto

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH　115　(1-2)　33-42　2002/06
Publisher: ELSEVIER SCIENCE BV
DOI： 10.1016/S0377-0273(01)00307-9 　

ISSN： 0377-0273

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Field explosion experiments using dynamite were carried out to investigate the effect of explosion energy and depth on the nature of explosion cloud. The scaling law of explosion was established among the energy, depth, and the nature of explosion cloud; shape, height and duration of flow out. The shape of explosion cloud changed systematically from funnel type via elongated to short types with increasing the scaled depth of explosion. At the shallow scaled depth, both scaled height and scaled duration increased with increasing scaled depth. Both values reached the maximum at 0.003-0.004 M/J(1/3) of cube-root scaled depth, and then decreased with increasing scaled depth. If the cube-root scaled depth was over about 0.01 m/J(t/3), we could not observe any explosion cloud on the ground surface. These experimental results should be applicable to the understanding of volcanic explosions if the buoyant effect of internal heat in the explosion cloud was negligible and ground medium is identical. We applied these results to the explosion clouds of Usu phreatic explosion at 14:53 h on 17 April 2000, and estimated that the explosion energy and the depth were 4 X 10(9) J and 6 in, respectively. Errors caused by uncertainty of scaling factors are less than one order of magnitude for the energy and depth. (C) 2002 Elsevier Science B.V. All rights reserved.
Obsidian in pumice from Krakatau Volcano : Obsidian formation by bubble collapse after magma vesiculation

OHBA Tsukasa, Goto Akio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2002　51-51　2002
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2002.2.0_51 　
Effects of explosion energy and depth to the formation of blast wave and crater: Field explosion experiment for the understanding of volcanic explosion Peer-reviewed

A Goto, H Taniguchi, M Yoshida, T Ohba, H Oshima

GEOPHYSICAL RESEARCH LETTERS　28　(22)　4287-4290　2001/11
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/2001GL013213 　

ISSN： 0094-8276

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We made field explosion experiments as an analogue of volcanic explosion to understand the relationship between the explosion condition and the resultant surface phenomena. The main parameters we employed were explosion depth and explosion energy. Through the experiments we confirmed that scaled depth, which is the depth divided by cube root of energy, is the main parameter determining the properties of explosive volcanism. The energy assigned to blast wave decreased exponentially against the scaled depth. The scaled crater diameter became maximum when the scaled depth was about 4 x 10(-3) m/J(1)/3. Scaled crater diameters by nuclear, chemical subsurface and some volcanic explosions were almost the same. From the scaling law, the overpressure at crater rim was estimated to be several MPa, which corresponded to typical rock strength. Probably the ground-forming materials were broken inside the area where overpressure exceeded their strength.
Field Explosion Experiments : Overpressure and Crater Size

Akio Goto, Mario Yoshida, Hiromitus Taniguchi, Tsukasa Ohba, Research Group on Volcanic Explosion

Proceedings of IAVCEI General Assembly 2000　210　2000/07
Field explosion experiment : kinetics of particles

Tsukasa Ohba, Akio Goto, Hiromitsu Taniguchi, Mario Yoshida

Proceedings of IAVCEI General Assembly 2000　160　2000/07
Field explosion experiment and volcanic explosion : Motive energy partition and shape of column

Tsukasa Ohba, Akio Goto, Hiromitsu Taniguchi, Mario Yoshida, Hiromitsu Oshima, Shintaro Hayashi

Eos, Transactions, American Geophysical Union　81　(22)　225　2000/05
Field explosion experiment and volcanic explosion : Scaling law for relations among energy, explosion depth, crater size and ballistics

Hiromitsu Taniguchi, Mario Yoshida, Tsukasa Ohba, Akio Goto, Hiromitsu Oshima

Eos, Transactions, American Geophysical Union　81　(22)　225　2000/05
Explosive volcanism of Kamchatka Peer-reviewed

Victor V. Ivanov, Hiromitsu Taniguchi, Victor V. Dvigaro, Akio Goto

Northeast Asian Studies　4　(4)　173-206　2000/03
Publisher:
ISSN： 1343-9332
Solubility of sulfide sulfur;the relative effect on compositions in silicate melts

Tsujimura T., Kitakaze A., Goto A., Taniguchi H., Akizuki M.

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2000　82-82　2000
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2000.2.0_82 　
A new model for volcanic earthquake at Unzen Volcano: Melt rupture model Peer-reviewed

A Goto

GEOPHYSICAL RESEARCH LETTERS　26　(16)　2541-2544　1999/08
Publisher: AMER GEOPHYSICAL UNION
DOI： 10.1029/1999GL900569 　

ISSN： 0094-8276

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Small earthquakes occurred inside the flowing magma during the 1991-1995 activities of Unzen Volcano. This paradoxical phenomenon can be explained when we consider that even a flowing magma fails brittly under the condition that the product of viscosity and strain rate of magma exceeds a certain threshold value. The estimated strain rate of magma in the conduit leads us to the conclusion the brittle failure is expected when the viscosity is over 10(11.5) Pa s. Laboratory measurements of samples show that this viscosity range can be attained when the temperature is under 850 degrees C in dry condition, and 800 degrees C with 0.6 wt.% water. Considering the temperature from Fe-Ti oxide geothermometer (780-880 degrees C) and the gas temperature (800 degrees C), the brittle failure condition could be satisfied inside the conduit. The melt failure by shear flow could be the source of the earthquakes occurred at the summit area.
Physical Explanation for Scaling Law Observed in Explosion Experiments

Goto A., Taniguchi H., Oba T., Yoshida M., Research Group on Volcanic Explosion

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　1999　136-136　1999
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.1999.2.0_136 　
Magma ascend model with consideration of stress dependency of viscosity

Goto Akio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　1998　56-56　1998
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.1998.2.0_56 　
Viscosity-equation for magmatic silicate melts over a wide temperature range.

Akio Goto, Itaru Maeda, Yasunori Nishida, Hiromitsu Oshima

Proceedings of the Unzen internAtional workshop : decade volcano and scientific drilling. At Shimabara city, Japan　100-105　1997/05
Empirical method of calculating the viscosity of peraluminous silicate melts at high temperatures Peer-reviewed

A Goto, H Oshima, Y Nishida

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH　76　(3-4)　319-327　1997/04
Publisher: ELSEVIER SCIENCE BV
ISSN： 0377-0273

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Shaw's method for the calculation of the viscosities of magmatic silicate liquids has been extended to multicomponent silicate melts in which Al2O3 exceeds the sum of alkali metal oxides and alkaline earth oxides. Al2O3 was converted to AlO2 and divided into the network-forming part, AlO20, and the excess part, AlO2*. AlO20 and AlO2* differed in their effect on viscosity. S-AlO2*(0) value, which evaluates the effect of AlO2* on viscosity, was chosen to compensate for the difference in Arrhenius slope between the data obtained by viscosity measurement and the data calculated from the chemical compositions other than AlO2*. From the viscosity measurement data of synthesized multicomponent melts, S-AlO2*(0) value was 5.6. This is smaller than the S-AlO2*(0) value of 6.7. Using the S-AlO2*(0) value with other S-i(0) values from Shaw (1972), the viscosities of peraluminous glassy rocks produced by the 1988-1989 eruptions of Tokachi-dake volcano (Hokkaido, Japan) were calculated. The calculated viscosities agreed well with the measured ones.
Self-potential studies in volcanic areas(4)-An attempt to estimate the in-situvalue of the electrokinetic coupling coefficient-.

Atsushi Oyamada, Hiromitsu Oshima, Yasunori Nishida, Akio Goto, Hiroyasu Furukawa

Journal of the Faculty of Science, Hokkaido University, Series VII(Geophysics)　10　(1)　79-87　1996/02
Publisher: Hokkaido University
Self-potential studies in volcanic areas (3) - Miyake-jima, Esan and Usu Peer-reviewed

Nishida Y, Matsushima N, Goto A, Nakayama Y, Oyamada A, Utsugi M, Oshima H

Journal of the Hokkaido University, Faculty of Science, Series VII: Geophysics　10　(1)　63-77　1996/02
Publisher: Hokkaido University
An experimental study on the rheological property of the dome lava of Unzen volcano.

Akio Goto, Hiromitsu Oshima, Yasunori Nishida, Hiromu Okada

Proceedings of the '95 international workshop on volcanoes commeorating the 50th anniversary of Mt. Showa-Shinzan. At Sobetsu town, Abuta town and Date city, Japan　44　1995/10
A numerical generator of low-frequency earthquakes

Takenaka Hiroshi, Goto Akio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　1995　19-19　1995
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.1995.2.0_19 　
Viscosity measurements of dome lava and volcanic ejecta of Unzen volcano Peer-reviewed

後藤章夫, 大島弘光, 西田泰典, 岡田弘

Bulletin of the Volcanological Society of Japan　39　(6)　267-271　1994/12
Publisher: Volcanological Society of Japan
DOI： 10.18940/kazan.39.6_267 　

ISSN： 0453-4360
Viscosity Measurements of High‐Alumina Rocks Ejected by 1988‐1989 Eruptions of Tokachi‐dake Volcano.

後藤章夫, 大島弘光, 西田泰典

北海道大学地球物理学研究報告　57　(57)　11-22　1994/10
Publisher:
DOI： 10.14943/gbhu.57.11 　

ISSN： 0439-3503
Estimation of the Effect of MnO on the Viscosity of Silicate Melts

Goto Akio

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　1994　226-226　1994
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.1994.2.0_226 　
北海道南西沖地震に伴う津波の現地調査-小樽から礼文島まで-

GOTO Akio

月刊海洋号外　7　153-158　1994

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Misc. 37

Bottom topography and sub-bottom structure of Okama crater lake, Zao volcano

山崎新太郎, 後藤章夫, 平野伸夫, 土屋範芳, 松中哲也

日本応用地質学会研究発表会講演論文集　2023　2023

ISSN： 0919-6021
Thermal activity surveys on crater lake Katanuma using limnological methods

後藤章夫, 知北和久

日本火山学会講演予稿集　2022　2022

ISSN： 2433-5320
Groundwater flow system inferred by estimates of hydrological, thermal and chemical budgets in Okama Crater Lake, Zao Volcano, Japan

知北和久, 後藤章夫, 岡田純, 三浦哲, 山本希

日本地球惑星科学連合大会予稿集(Web)　2021　2021
北海道南西沖地震に伴う津波 : 小樽から礼文島まで (復刻北海道南西沖地震と津波 : 2部津波(1))

後藤章夫, 高橋浩晃, 宇津木充, 小野忍, 西田泰典, 大島弘光, 笠原稔, 竹中博士, 斉田智治

月刊地球 = Chikyu monthly　42　(4)　214-219　2020/04
Publisher: 海洋出版
ISSN： 0387-3498
Estimates of hydrological, thermal and chemical budgets of Okama Crater Lake, Zao Volcano, Japan: A preliminary study

知北和久, 後藤章夫, 岡田純, 三浦哲, 山本希

日本地球惑星科学連合大会予稿集(Web)　2020　2020
Geological and petrological investigation on the Maruyamazawa fumarolic geothermal field, at Zao volcano

井村匠, 伴雅雄, 常松佳恵, 後藤章夫, 岡田純

日本火山学会講演予稿集　2020　2020

ISSN： 2433-5320
蔵王山現地調査報告(2012‐2017)

後藤章夫, 土屋範芳, 平野伸夫, 松中哲也, 久利美和

日本火山学会講演予稿集　2017　249　2017/09/21

DOI： 10.18940/vsj.2017.0_249 　

ISSN： 2433-5320
Unzen Heisei lava advanced not by flow but by slide

Goto Akio, Fukui Keiichi, Matsushima Takeshi

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2016　(0)　12-12　2016
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2016.0_12 　

ISSN： 2433-5320
蔵王火山で過去100年間に見られた活発化と現在の状況

後藤章夫, 土屋範芳, 平野伸夫, 渡邊隆広, 松中哲也, 久利美和, 宇野正起, 岡本敦, 中村謙吾, 町澄秋

日本地球惑星科学連合大会予稿集(Web)　2016　ROMBUNNO.SVC47‐P04 (WEB ONLY)　2016
Study on monitoring of volcanic activity using <sup>129</sup>I/<sup>127</sup>I ratios in hydrothermal system at Zao volcano

松中哲也, 笹公和, 末木啓介, 柴山尚大, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

KEK Proceedings (Web)　(2014-7)　47-51 (WEB ONLY)　2014/11
蔵王火山御釜湖沼および丸山沢噴気地熱地帯温泉水の地球化学分析

渡邊隆広, 土屋範芳, 後藤章夫, 平野伸夫, 宇野正起, 松中哲也, 細田憲弘

日本第四紀学会講演要旨集　44　167　2014/09/05
P1-08 Fumarole temperature monitoring and geochemical analysis of hot spring water at Maruyama-sawa geothermal area, Zao volcano

goto Akio, Watanabe Takahiro, Matsunaka Tetsuya, Tsuchiya Noriyoshi

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2014　(0)　126-126　2014
Publisher: The Volcanological Society of Japan
ISSN： 2433-5320
B2-06 Viscosity measurements of Unzen Fugen-dake Heisei lava

Goto A., Hiraga T., Ishibashi H.

Programme and abstracts the Volcanological Society of Japan　2013　76-76　2013/09/29
Publisher: Volcanological Society of Japan
DOI： 10.18940/vsj.2013.0_76 　

ISSN： 2433-5320
北海道南西沖地震に伴う津波 : 小樽から礼文島まで (総特集津波災害)

後藤章夫, 高橋浩晃, 宇津木充

月刊地球　35　(1)　47-52　2013/01
Publisher: 海洋出版
ISSN： 0387-3498
P08 High-sampling Ground Tilt Observations at Kliuchevskoi Volcano, Kamchatka

Matsushima T., Takahashi H., Aoyama H., Nakagawa M., Miyamachi H., Goto A., Sergey Serovetnikov, Yaroslav Muravyev, Evgeny Gordeev

PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2012　106-106　2012
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.2012.0_106 　
P17 Development of an operation base car for MOVE

Goto Akio, Ichihara Mie, Taniguchi Hiromitsu

Programme and abstracts the Volcanological Society of Japan　2009　(0)　117-117　2009/10/10
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2009.0_117 　

ISSN： 2433-5320
防災・警備分野におけるロボット火山探査移動観測ステーションMOVEの開発

谷口宏充, 後藤章夫, 市原美恵

ロボット　(187)　10-16　2009/03/20
Publisher: 日本ロボット工業会
ISSN： 0387-1940
P99 Observational maneuvers at Oshima Volcano of the Mobile Observatory for Volcanic Explosions, MOVE(THE VOLCANOLOGICAL SOCIETY OF JAPAN 2006 FALL MEETING)

Taniguchi H, Goto A, Ichihara M, Yamada I, Kaneko K, Shimano T, Maeno F, Kuri M, Ohba T, Kogure M, Inayama N, Kato A, Tsuchida Y, Matsuyama A, Tanaka K

Programme and abstracts the Volcanological Society of Japan　2006　(0)　213-213　2006/10/23
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2006.0_213 　

ISSN： 2433-5320
高圧ガス解放時における解放過程/空間の影響

古川剛, 後藤章夫, 小川俊広, 佐宗章弘, 谷口宏充

衝撃波シンポジウム講演論文集　2005　227-228　2006/03/16
2A1-S-057 Development of Mobile Observatory For Volcanic Explosion (MOVE)(Construction Robot and Mechatronics 1,Mega-Integration in Robotics and Mechatronics to Assist Our Daily Lives)

Sugawara Kazuhiro, Fujita Kensho, Oohira Shuji, Taniguchi Hiromitsu, Goto Akio, Ichihara Mie

Robomech　2005　(0)　176-176　2005/06/09
Publisher: 一般社団法人日本機械学会
Development of Mobile Observatory For Volcanic Explosion(MOVE)

谷口宏充, 後藤章夫, 市原美恵, 菅原一宏, 藤田健昇, 大平修二

日本機械学会ロボティクス・メカトロニクス講演会講演論文集(CD-ROM)　2005　2A1-S-057　2005/06/09
B44 A test traveling of the Mobile Observatory for Volcanic Explosion (MOVE)

Goto A, Ichihara M, Taniguchi H, Maeno F, Kogure M, Koyama M, Fujita K, Yamashita S, Sugawara K, Kondo N, Ohira S, Iguchi M

Programme and abstracts the Volcanological Society of Japan　2004　(0)　108-108　2004/10/19
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2004.0_108 　

ISSN： 2433-5320
P19 Regularity and variability of Onikobe geyser

Ichihara Mie, Nishimura Takeshi, Goto Akio, Taniguchi Hiromitsu

Programme and abstracts the Volcanological Society of Japan　2004　(0)　129-129　2004/10/19
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2004.0_129 　

ISSN： 2433-5320
総合力としての砂防 CGを駆使した最新シミュレーション技術-富士山噴火時の溶岩流を表現-

藤田英輔, 日高政隆, 海野進, 後藤章夫

土木施工　45　(6)　038-041　2004/06/01
Publisher: 山海堂
ISSN： 0387-0790
Magmatic Expression of Plate Subduction beneath East Asia in the Mesozoic through Cenozoic

Northeast Asian studies　(9)　179-219　2004
Publisher: 東北大学東北アジア研究センタ-
ISSN： 1343-9332
Simulations for volcanic thermal fluid dynamics and its application to the evaluation and prediction of the effects on environments (I)

FUJITA Eisuke, HIDAKA Masataka, MINATO Akihiko, UMINO Susumu, NONAKA Miyuki, TORAMARU Atsushi, GOTO Akio, NISHIMURA Takeshi, ICHIHARA Mie, YAMAMOTO Asao, SUSAWA Hiromoto, UKAWA Motoo, SATO Kazuo

Programme and abstracts the Volcanological Society of Japan　2002　(2)　2002/10/22
Publisher: 特定非営利活動法人日本火山学会
ISSN： 2433-5320
Video image analysis of the eruptions on Stromboli Volcano

Goto Akio, Minato Akihiko, Ichihara Mie, Nishimura Takeshi, Fujita Eisuke

Programme and abstracts the Volcanological Society of Japan　2002　(2)　190-190　2002/10/22
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2002.2.0_190 　

ISSN： 2433-5320
Explosion parameters and mechanism of the 2000 Usu explosive eruption

Taniguchi H, Goto A, Ohba T, Yokoo A, Miyamoto T, Oshima H

Programme and abstracts the Volcanological Society of Japan　2000　(2)　36-36　2000/09/30
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2000.2.0_36 　
Explosin Energy and Depth of Usu 2000 Explosive Eruption

Yokoo Akihiko, Taniguchi Hiromitsu, Goto Akio, Miyamoto Tsuyoshi, Ohba Tsukasa, Ohba Tsukasa, Hiromitsu Ohshima, Research Group on Volcanic Explosion

Programme and abstracts the Volcanological Society of Japan　2000　(2)　37-37　2000/09/30
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.2000.2.0_37 　
A numerical generator of monochromatic events.

竹中博士, 後藤章夫

日本地震学会秋季大会講演予稿集　1995　1995
珪酸塩メルトの破壊-雲仙普賢岳山頂部で発生する地震の原因

後藤章夫

日本火山学会講演予稿集, 1995年秋季大会　45　1995
Earthquake off the southwest of Hokkaido and tidal waves.Tidal waves caused by the earthquake off the southwest of Hokkaido.From Otaru to Rebunto Island.

後藤章夫, 高橋浩晃, 宇津木充, 小野忍, 西田泰典, 大島弘光, 笠原稔, 竹中博士, 斉田智治

月刊海洋　(Gogai 7)　153-158　1994/09

ISSN： 0916-2011
Seismic Experiment on Showa-Shinzan Lava Dome Using Ground-Firework Shot.

KANNO TOMOYUKI, MAEKAWA TOKUMITSU, SUZUKI ATSUO, GOTO AKIO, OSHIMA HIROMITSU, MORI HITOSHI, OKADA HIROMU

地球惑星科学関連学会合同大会予稿集　1994　372-124　1994/03
Publisher: The Volcanological Society of Japan
DOI： 10.18940/vsj.1992.2.0_124 　
A Field Survey of Tsunami Generated by the Hokkaido-Nansei-Oki Earthquake. From Otaru to Rebun Island.

GOTO AKIO, TAKAHASHI HIROAKI, UTSUGI MITSURU, ONO SHINOBU, NISHIDA YASUNORI, OSHIMA HIROMITSU, KASAHARA MINORU, TAKENAKA HIROSHI, SAITA TOMOHARU

日本地震学会秋季大会講演予稿集　1993　53　1993/09
Viscosity Measurement of Volcanic Ejecta of Tokachi-dake Volcano

Goto Akio, Ohshima Hiromitu

Programme and abstracts the Volcanological Society of Japan　1992　(2)　87-87　1992/11/09
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.1992.2.0_87 　
Viscosity Measurement of Volcanic Ejecta and Dome Lava of Unzen Volcano

Goto Akio, Hoshima Hiromitsu, Okada Hiromu

Programme and abstracts the Volcanological Society of Japan　1992　(2)　140-140　1992/11/09
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.1992.2.0_140 　
Viscosity meajurement of the 1988-1989 volcanic ejecta of Tokachi-Dake volcano

Goto Akio, Ohshima Hiromitsu, Nishida Yasunori

Programme and abstracts the Volcanological Society of Japan　1992　(1)　7-7　1992/04/07
Publisher: 特定非営利活動法人日本火山学会
DOI： 10.18940/vsj.1992.1.0_7

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Books and Other Publications 2

大陸と日本をつなぐ自然史 : 地質・生態系の総合研究最前線

鹿野, 秀一, 平野, 直人, 千葉, 聡

古今書院　2021/01

ISBN: 9784772253123
火山爆発に迫る

後藤章夫, 市原美恵, 谷口宏充

東京大学出版会　2008

Presentations 114

A molecular-scale origin of shear thinning and brittle failure of silicate melt

Satoshi Okumura, Kentaro Uesugi, Akio Goto, Kazuhisa Matsumoto, Tatsuya Sakamaki

AGU23　2023/12/13
Glass-like fragmentation of high-temperature silicate melts

Atsuko Namiki, Satoshi Okumura, Akio Goto, Tsutomu Yamada

AGU23　2023/12/12
蔵王火山火口湖・御釜の現在の活動状況について

後藤章夫, 知北和久, 山崎新太郎, 岡田純, 松中哲也, 土屋芳範, 平野伸夫, 大八木英夫, 山口高志

日本火山学会秋季大会　2023/10/19
A study on water cycles and geothermal processes in a crater lake: Okama in Zao Volcano

Kazuhisa A. Chikita, Akio Goto, Jun Okada, Hideo Oyagi, Takashi Yamaguchi

Japan Geoscience Union Meeting 2023　2023/05/24
Bottom topography and the sub-bottom structure revealed by acoustic technology and small ROV for the Okama creter, Zao volcano

Shintaro Yamasaki, Akio Goto, Nobuo Hirano, Noriyoshi Tsuchiya, Tetsuya Matsunaka

Japan Geoscience Union Meeting 2023　2023/05/25
伊豆大島溶岩のレオロジー特性と内部組織

後藤章夫

2018/09/26
蔵王山現地調査報告（2012－2017）

後藤章夫, 土屋範芳, 平野伸夫, 松中哲也, 久利美和

日本火山学会秋季大会　2017/09/21
伊豆大島溶岩のレオロジー特性

後藤章夫

日本地球惑星科学連合2017年大会　2017/05/20
雲仙普賢岳平成溶岩は流れずに滑りで前進していた

後藤章夫, 福井敬一, 松島健

日本火山学会秋季大会　2016/10/13
水準測量より明らかにした東北地方太平洋沖地震後の鳴子地域の上下地殻変動

高橋菜緒子, 畠山雅将, 百合本はる妃, 本田雄生, 塚本雄也, 後藤章夫, 太田雄策

日本地球惑星科学連合2016年大会　2016/05/22
蔵王火山で過去100年間に見られた活発化と現在の状況

後藤章夫, 土屋範芳, 平野伸夫, 渡邊隆広, 松中哲也, 久利美和, 宇野正起, 岡本敦, 中村謙吾, 町澄秋

日本地球惑星科学連合2016年大会　2016/05/22
蔵王山における火口湖と地熱帯で観測されたヨウ素同位体比の低下

松中哲也, 笹公和, 高橋努, 松村万寿美, 末木啓介, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 久利美和, 高橋正明, 風早康平, 宮城磯治, 松崎浩之

第18回AMSシンポジウム　2016/03/04
蔵王山に於ける全磁力観測

市來雅啓, 海田俊輝, 出町知嗣, 中山貴史, 平原聡, 山本希, 三浦哲, 後藤章夫, 森山多加志, 芥川真由美, 大森茂生, 小野幸治, 小林宰, 松浦茂郎

CA研究会　2016/01/06
Iodine isotopic ratio in crater lake and geothermal area at Zao volcano, Japan International-presentation

Tetsuya Matsunaka, Kimikazu Sasa, Keisuke Sueki, Tsutomu Takahashi, Masumi Matsumura, Akio Goto, Takahiro Watanabe, Noriyoshi Tsutchiya, Nobuo Hirano, Hiroyuki Matsuzaki

EA-AMS6　2015/10/05
雲仙普賢岳平成溶岩のレオロジー

後藤章夫

日本火山学会秋季大会　2015/09/28
Changes in ¹²⁹I/¹²⁷I ratio of crater lake and volcanic activity at Zao volcano, Japan International-presentation

T. Matsunaka, K. Sasa, K. Sueki, T. Takahashi, M. Matsumura, A. Goto, T. Watanabe, N. Tsuchiya, N. Hirano, H. Matsuzaki

ENVIRA2015　2015/09/21
蔵王山火口湖ヨウ素同位体比の経時変化と火山活動に関する研究

松中哲也, 笹公和, 末木啓介, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

第16回「環境放射能」研究会　2015/03/09
蔵王山における火山活動とヨウ素同位体比の変動

松中哲也, 笹公和, 末木啓介, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

第17回AMSシンポジウム　2015/03/02
ヨウ素同位体比を用いた蔵王山火山活動のモニタリング研究

松中哲也, 笹公和, 末木啓介, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

日本質量分析学会・2014年度同位体比部会　2014/11/26
蔵王山・丸山沢噴気地熱地帯の噴気温測定と温泉水化学分析

後藤章夫, 渡邊隆広, 松中哲也, 土屋範芳

日本火山学会秋季大会　2014/11/02
蔵王山火山湖および温泉における¹²⁹I/¹²⁷I比の分布

松中哲也, 笹公和, 末木啓介, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

日本陸水学会第79回大会　2014/09/10
蔵王火山御釜湖沼および丸山沢噴気地熱地帯温泉水の地球化学分析

渡邊隆広, 土屋範芳, 後藤章夫, 平野伸夫, 宇野正起, 松中哲也, 細田憲弘, 東北大学蔵王御釜調査グループ

日本第四紀学会2014年大会　2014/09/05
Study on monitoring of volcanic activity using ¹²⁹I/¹²⁷I ratios in crater lake and hot spring at Zao volcano International-presentation

Tetsuya Matsunaka, Kimikazu Sasa, Keisuke Sueki, Nao Shibayama, Tsutomu Takahashi, Masumi Matsumura, Yukihiko Satou, Hiroyuki Matsuzaki, Akio Goto, Takahiro Watanabe, Noriyoshi Tsuchiya, Nobuo Hirano, Akihisa Kizaki

AMS-13　2014/08/24
圧電ブザーとノートパソコンを用いた地震波探査教材の開発

後藤章夫

日本地球惑星科学連合2014年大会　2014/04/28
水準測量より明らかにした東北地方太平洋沖地震による鳴子地域の上下地殻変動

塚本雄也, 杉山賢一, 藤田和果奈, 渡辺慶太郎, 渡邉虹水, 高畑明浩, 松岡萌, 後藤章夫, 太田雄策

日本地球惑星科学連合2014年大会　2014/04/28
蔵王山熱水系における¹²⁹I/¹²⁷Iを用いた火山活動モニタリングの試み

松中哲也, 笹公和, 末木啓介, 柴山尚大, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

日本地球惑星科学連合2014年大会　2014/04/28
Geochemical characteristics of natural water from the Okama crater lake and Kamoshika hot springs in Zao volcano area, Japan International-presentation

T. Watanabe, N. Tsuchiya, H. Onodera, A. Goto, N. Hirano, A. Kizaki, Q. Lu, T. Eto, K. Sakurai, R. Takeda, R. Oyanagi, R. Yamada, N. Hosoda

11th International Workshop on WATER DYNAMICS　2014/03/12
蔵王山熱水系における129I/127I比を用いた火山活動モニタリングの試み

松中哲也, 笹公和, 末木啓介, 柴山尚大, 高橋努, 松村万寿美, 佐藤志彦, 松崎浩之, 後藤章夫, 渡邊隆広, 土屋範芳, 平野伸夫, 木崎彰久

第15回環境放射能研究会　2014/03/06
雲仙普賢岳平成溶岩の粘性係数測定

後藤章夫, 平賀岳彦, 石橋秀巳

日本火山学会秋季大会　2013/10
Viscosity measurements of crystal-bearing natural lava samples from Unzen volcano, Japan International-presentation

Goto, A, Hiraga, T, Ishibashi, H

IAVCEI 2013 General Assembly　2013/07/20
無人火山探査移動観測ステーション“MOVE”開発の総括

後藤章夫, 谷口宏充, 市原美恵

日本地球惑星科学連合2013年大会　2013/05
カムチャッカ・クリチェフスカヤ火山における高サンプリング傾斜変動観測

松島健, 高橋浩晃, 青山裕, 中川光弘, 宮町宏樹, 後藤章夫, Serovetnikov Sergey, Muravyev Yaroslav, Gordeev Evgeny

日本火山学会秋季大会　2012/10
Surveillance of Volcanic Unrest - New Developments in Multi-Disciplinary Monitoring Methods. International-presentation

Johnson, J, Anderson, J, Sanderson, R, Goto, A, Waite, G, Palma, J

2011AGU Fall Meeting　2011/12
ストロンボリ火山で収録された空振波形の周波数解析

後藤章夫, Maurizio Ripepe

日本火山学会秋季大会　2011/10
チリ・ビラリカ火山で観測された低周波空振の発振機構

後藤章夫, Jeffrey Johnson

日本地球惑星科学連合2011年大会　2011/05
Vent geometry detected from infrasound observation on Villaricca volcano, Chile International-presentation

A. Goto, J. B. Johnson, R. W. Sanderson, J. Anderson, N. R. Varley

2010AGU Fall Meeting　2010/12
Development and a Maneuver of “Mobile Observatory for Volcanic Explosion (MOVE)”–part 2 – International-presentation

Akio Goto, Hiromitsu Taniguchi, Mie Ichihara, Katsuya Kaneko, Kazuto Saiki

Cities on Volcanoes 6　2010/05
MOVE操縦基地局車の開発

後藤章夫, 市原美恵, 谷口宏充

日本火山学会秋季大会　2009/10
伊豆大島火山1951年溶岩流の表面形態と石基組織

小栗尚樹, 宮本毅, 後藤章夫

日本火山学会秋季大会　2009/10
軽量無人観測機SKY-1を用いた阿蘇山プルームの観測

小島知子, 佐伯和人, 後藤章夫, 谷口宏充

第26回エアロゾル科学・技術討論会　2009/08/19
Goto (1997) の粘性係数計算法の再評価

後藤章夫

日本地球惑星科学連合2009年大会　2009/05
ストロンボリ火山の噴火映像と高速度収録された空振波形の解析

後藤章夫, Ripepe, M, Lacanna, G

日本火山学会秋季大会　2008/10
Synchronized analysis of high-rate-sampled acoustic waves and video images on Stromboli volcano International-presentation

Goto, A, Ripepe, M, Lacanna, G

IAVCEI 2008 General Assembly　2008/08
伊豆大島火山1951 年溶岩流の表面形態

小栗尚樹, 宮本毅, 後藤章夫, 谷口宏充

日本地球惑星科学連合2008年大会　2008/05
スメル火山での噴煙と空振の近傍観測－その関係と実験結果との共通性－

井口正人, 古川剛, 小川俊広, 佐宗章弘, 谷口宏充, 大林茂

日本火山学会秋季大会　2007/11
Development and a Maneuver of “Mobile Observatory for Volcanic Explosion (MOVE)” International-presentation

Hiromitsu Taniguchi, Mie Ichihara, Fukashi Maeno, Miwa Kuri, Taketo Shimano, Katsuya Kaneko, Isao Yamada

Cities on Volcanoes 5　2007/11
火山爆発における圧力解放と物体放出に関する実験的研究

加藤鮎, 谷口宏充

地球惑星科学関連学会　2007/05
Analogue Experiments of Volcanic Explosions Using High Pressure Gas International-presentation

Takeshi Furukawa, Toshihiro Ogawa, Akihiro Sasoh, Hiromitsu Taniguchi, Shigeru Obayashi

2006 AGU Fall Meeting　2006/12
高圧ガスを用いた火山爆発模擬実験－その4：圧力波形－

古川剛, 小川俊広, 佐宗章弘, 谷口宏充, 大林茂

日本火山学会秋季大会　2006/10
高圧ガスを用いた火山爆発模擬実験－その3：噴出物運動解析－

古川剛, 小川俊広, 佐宗章弘, 谷口宏充

地球惑星科学関連学会　2006/05
火山探査移動観測ステーションMOVEの伊豆大島火山観測演習

谷口宏充, 後藤章夫, 市原美恵, 山田功夫, 金子克哉, 嶋野岳人, 前野深, 久利美和, 大場司, 小暮昌史, 稲山尚利, 加藤鮎, 土田庸夫, 松山明男, 田中克己

日本火山学会講演予稿集　2006
LavaSIMによるエトナ山2001年噴火溶岩流シミュレーション

PROIETTI Cristina, MARCELLA Maria, COLTELLI Mauro, 海野進, 後藤章夫, 藤田英輔

日本火山学会講演予稿集　2006
高圧ガスを用いた火山爆発模擬実験－その2：スケール則－

古川剛, 小川俊広, 佐宗章弘, 谷口宏充

日本火山学会秋季大会　2005/10
高圧ガスを用いた火山爆発模擬実験

古川剛, 佐宗章弘, 谷口宏充

地球惑星科学関連学会　2005/05
高圧ガス解放による火山爆発模擬実験

古川剛, 佐宗章弘

平成１６年度衝撃波シンポジウム　2005/03/17
ブラスト波の挙動に対する有限時間エネルギー開放プロセスの影響

古川剛, 佐宗章弘

平成１６年度衝撃波シンポジウム　2005/03/17
火山探査移動観測ステーション（MOVE）の走行試験

市原美恵, 谷口宏充, 前野深, 小暮昌史, 小山将明, 藤田健昇, 山下誠二, 菅原一宏, 近藤尚志, 大平修二, 井口正人

日本火山学会秋季大会　2004/10
Effect of Thermal Memory on Viscosity Increase in Magmatic Silicate Melts at Low Temperature without Crystallization International-presentation

Hiromitsu Taniguchi, Yasunori Nishida, Hiromitsu Oshima

2004 Western Pacific Geophysics Meeting　2004/08
爆発的噴火のさらなる理解を目指した室内爆発実験

佐宗章弘, 市原美恵, 谷口宏充

地球惑星科学関連学会　2004/05
溶岩流の結晶配向性～伊豆大島LC?溶岩流の例～

菅野繁広

地球惑星科学関連学会　2004/05
火山探査移動観測ステーションと搭載観測システムの開発

谷口宏充, 市原美恵

地球惑星科学関連学会　2004/05
SPHコードによる野外爆破実験のシミュレーション

高田淑子, 市原美恵, 谷口宏充

地球惑星科学関連学会　2004/05
水中爆発による空振の発生と波形形成過程について

市原美恵, 田中克己, 大島弘光, 谷口宏充

地球惑星科学関連学会　2004/05
鬼首間欠泉の規則性と変動について

市原美恵, 西村太志, 後藤章夫, 谷口宏充

日本火山学会講演予稿集　2004
粘性の時間変化に対する"熱記憶"の影響

谷口宏充

日本火山学会秋季大会　2003/10/11
低温での時間に対する粘性増加‐“熱記憶”の影響‐

後藤章夫, 谷口宏充

日本岩石鉱物鉱床学会学術講演会講演要旨集　2003/09/28
伊豆大島1986年LA溶岩流の表面形態

菅野繁広, 後藤章夫, 谷口宏充

日本岩石鉱物鉱床学会学術講演会講演要旨集　2003/09/28
マグマを模擬した2つの対照的な珪酸塩融体の混合による諸物性の変化

金杉諭, 後藤章夫, 谷口宏充

日本岩石鉱物鉱床学会学術講演会講演要旨集　2003/09/28
Viscosity measurements of hydrous silicate melts using fiber elongation method International-presentation

Hiromitsu TANIGUCHI, Arashi KITAKAZE

XXIII General Assembly of the International Union of Geodesy and Geophysics　2003/06/30
The viscosity of diopside-pottasium feldspar melt system International-presentation

Satoshi KANASUGI, Hiromitsu TANIGUCHI

XXIII General Assembly of the International Union of Geodesy and Geophysics　2003/06/30
Development of the lava flow simulation code 'LavaSIM' for an advanced hazard system in the 'VTFS' project International-presentation

Masataka HIDAKA, Asao YAMAMOTO, Susumu UMINO, Eisuke FUJITA

XXIII General Assembly of the International Union of Geodesy and Geophysics　2003/06/30
Simulations for volcanic thermal fluid dynamics and its application to the evaluation and prediction of the effects on environments: VTFS-project International-presentation

Eisuke FUJITA, Masataka HIDAKA, Akihiko MINATO, Susumu UMINO, Miyuki NONAKA, Atsushi TORAMARU, Mie ICHIHARA, Takeshi NISHIMURA, Kazuo SATO, Motoo UKAWA

XXIII General Assembly of the International Union of Geodesy and Geophysics　2003/06/30
Underwater explosion experiments for the understanding of submarine explosive eruption International-presentation

Akihiko YOKOO, Mie ICHIHARA, Hiromitsu OSHIMA, Hiroshi AOYAMA, Tokumitsu MAEKAWA, Hiromitsu TANIGUCHI

XXIII General Assembly of the International Union of Geodesy and Geophysics　2003/06/30
伊豆大島1986 年LA 溶岩流の表面形態

菅野繁広, 谷口宏充

地球惑星科学関連学会　2003/05
火山探査移動観測ステーションMOVE の開発について

谷口宏充, 市原美恵, 横尾亮彦

地球惑星科学関連学会　2003/05
ストロンボリ火山噴火のビデオ画像解析

湊明彦, 市原美恵, 西村太志, 藤田英輔

日本火山学会秋季大会　2002/10/22
火山熱流体シミュレーションと環境影響予測手法の開発 VTFS (I) (2) 3次元溶岩流シミュレーションコードLavaSIMの検証

日高政隆, 山本朝男, 海野進, 後藤章夫, 藤田英輔

日本火山学会講演予稿集　2002/10/22
クラカトア火山の軽石中の黒曜岩マグマ発泡後の気泡崩壊による黒曜岩形成

大場司, 後藤章夫

日本火山学会講演予稿集　2002/10/22
火山熱流体シミュレーションと環境影響予測手法の開発 VTFS (I) (1) プロジェクトの概要

藤田英輔, 日高政隆, 海野進, 寅丸敦志, 後藤章夫, 西村太志, 市原美恵, 山本朝男, 諏沢寛源

日本火山学会講演予稿集　2002/10/22
ガラス繊維引き伸ばし法による含水メルトの粘性測定法

谷口宏充, 北風嵐

地球惑星科学関連学会　2002/05
マグマ模擬物質としての透輝石－カリ長石系融体の物性測定

金杉諭, 谷口宏充

地球惑星科学関連学会　2002/05
含水メルトの粘性測定に向けたガラスの水和実験（序報）

地球惑星科学関連学会　2001/06
高温下における火星マグマの粘性測定

葛西志津, 大谷栄治, 谷口宏充, 近藤忠

地球惑星科学関連学会　2001/06
マグマに対する硫黄溶解度とくに珪酸塩ガラス組成と硫黄含有量相関について

辻村知之, 北風嵐, 後藤章夫, 谷口宏充, 秋月瑞彦

日本地球化学会年会講演要旨集　2000/09/25
有珠山2000年噴火における爆発エネルギー量と爆発深度

横尾亮彦, 谷口宏充, 宮本毅, 大場司, 大島弘光

日本火山学会秋季大会　2000/09/13
マグマに対する硫黄溶解度の実験的研究とくに珪酸塩ガラス組成との関係について

辻村知之, 北風嵐, 後藤章夫, 谷口宏充, 秋月瑞彦

日本火山学会講演予稿集　2000/09/13
有珠山2000年噴火の爆発パラメータと爆発機構

谷口宏充, 後藤章夫, 大場司, 横尾亮彦, 宮本毅, 大島弘光

日本火山学会講演予稿集　2000/09/13
Field explosion experiment : kinetics of particles International-presentation

Tsukasa Ohba, Hiromitsu Taniguchi, Mario Yoshida

IAVCEI General Assembly 2000　2000/07
Field Explosion Experiments: Overpressure and Crater Size International-presentation

IAVCEI General Assembly 2000　2000/07
野外爆発実験における爆風圧・クレーター径・爆煙形状と薬量・発破深度の関係

大場司, 吉田真理夫, 西村太志, 谷口宏充, 火山爆発研究グループ

地球惑星科学関連学会　2000/06
Explosion Energy and Disaster Distribution of Usu 2000 Explosive Eruption International-presentation

Hiromitsu Taniguchi, Akihiko Yokoo, Tsuyoshi Miyamoto, Tomoaki Eguchi, Tsukasa Ohba, Mario Yoshida, Hiroaki Yamamoto, Tomonori Ezawa, Yoshinobu Akatsu, Fukashi Maeno, Toshiaki Hasenaka, Shintaro Hayashi, Hiromitsu Oshima

2000 Western Pacific Geophysics Meeting　2000/06
Field explosion experiment and volcanic explosion : Motive energy partition and shape of column International-presentation

Tsukasa Ohba, Hiromitsu Taniguchi, Mario Yoshida, Hiromitsu Oshima, Shintaro Hayashi

2000 Western Pacific Geophysics Meeting　2000/06
Field explosion experiment and volcanic explosion : Scaling law for relations among energy, explosion depth, crater size and ballistics International-presentation

Hiromitsu Taniguchi, Mario Yoshida, Tsukasa Ohba, Hiromitsu Oshima

2000 Western Pacific Geophysics Meeting　2000/06
爆破実験でみられたスケーリング則に対する物理的解釈

谷口宏充, 大場司, 吉田真理夫, 火山爆発研究グループ

日本火山学会秋季大会　1999/10/09
野外爆発実験と火山爆発現象:地震波およびインフラソニック波の観測

大島弘光, 加藤幸司, 青山裕, 谷口宏充, 火山爆発研究グループ

地球惑星科学関連学会　1999/06
過剰圧が低い場合の火山灰生成モデル

地球惑星科学関連学会　1999/06
粘性の応力依存性を考慮したマグマ上昇モデル

後藤章夫

日本火山学会秋季大会　1998/10
Effect of thermal history on the viscosity change with time.

後藤章夫

地球惑星科学関連学会合同大会予稿集　1998/05
溶岩の粘性と噴出率から推定された火山性地震の発生機構～雲仙普賢岳への適用～

後藤章夫

日本岩石鉱物鉱床学会　1998/02
Viscosity-equation for magmatic silicate melts over a wide temperature range International-presentation

Itaru Maeda, Yasunori Nishida, Hiromitsu Oshima

Unzen internAtional workshop : decade volcano and scientific drilling. At Shimabara city, Japan　1997/05
広範囲の温度で適用可能な溶融火山岩の粘性係数計算法

前田亟, 西田泰典, 大島弘光

地球惑星科学関連学会　1997/03
低周波地震の数値発生モデル

竹中博士

日本火山学会秋季大会　1995/10
珪酸塩メルトの破壊～雲仙普賢岳山頂部で発生する地震の原因～

後藤章夫

日本火山学会秋季大会　1995/10
An experimental study on the rheological property of the dome lava of Unzen volcano International-presentation

Hiromitsu Oshima, Yasunori Nishida, Hiromu Okada

95 international workshop on volcanoes commeorating the 50th anniversary of Mt. Showa-Shinzan. At Sobetsu town, Abuta town and Date city, Japan　1995/10
A numerical generator of monochromatic events.

竹中博士, 後藤章夫

日本地震学会秋季大会講演予稿集　1995/09
Estimation of the Effect of MnO on the Viscosity of Silicate Melts.

後藤章夫

日本火山学会講演予稿集　1994/10
高アルミナ質岩の高温での粘性係数計算法

後藤章夫

地球惑星科学関連学会　1994/03
溶岩流の形態と粘性,降状強度

石川剛, 荒牧重雄

地球惑星科学関連学会　1994/03
昭和新山溶岩ドームにおける地上爆裂型花火の地震動観測

菅野智之, 前川徳光, 鈴木敦夫, 大島弘光, 森済, 岡田弘

地球惑星科学関連学会　1994/03
Morphorogy, Viscosity and Yield Strength of Lava Flows.

石川剛, 荒牧重雄, 後藤章夫

地球惑星科学関連学会合同大会予稿集　1994/03
A Field Survey of Tsunami Generated by the Hokkaido-Nansei-Oki Earthquake. From Otaru to Rebun Island.

後藤章夫, 高橋浩晃, 宇津木充, 小野忍, 西田泰典, 大島弘光, 笠原稔, 竹中博士, 斉田智治

日本地震学会秋季大会講演予稿集　1993/09
十勝岳噴出物の粘性係数測定

大島弘光

日本火山学会秋季大会　1992/11
雲仙火山の噴出物及びドーム溶岩の粘性係数測定

大島弘光, 岡田弘

日本火山学会秋季大会　1992/11
1988-1989年十勝岳噴出物の粘性係数測定

大島弘光, 西田泰典

地球惑星科学関連学会　1992/04

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Research Projects 12

蔵王火山表面活動調査 Competitive

2012/04 - Present
Explosive Volcanism Competitive

1999/02 - Present
Rheology of magma Competitive

1990/04 - Present
噴火の潜在性を秘めた静穏な火口湖の活動度評価の試み

後藤章夫, 土屋範芳, 山崎新太郎, 松中哲也, 知北和久, 平野伸夫

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(C)

Institution: 東北大学

2021/04/01 - 2024/03/31

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噴火の潜在性を秘めた静穏な火口湖の活動度評価手法を確立するために，蔵王火山の火口湖・御釜をテストフィールドとして，①水・熱・化学物質収支の評価による地下熱水系の影響評価，②湖水中のヨウ素同位体比（129I/127I比）分析による地下深部起源物質の寄与の検出，③映像・音響探査による湖底調査を開始した．令和3年度は計4回の現地調査を行い，5月18日から9月28日の間は，水収支の推定に必要な降水量や湖面蒸発量を求める気象連続観測を湖岸で行った．8月5日には，御釜湖底の様子を水中ドローンで調査した．御釜では2018年に先行研究でソナーを用いた探査が実施され，平坦な湖底のほぼ中心部に丘状の地形が発見され，そこから上方に伸びる小物体群を示す反射が報告されている．溶存物質も考慮して御釜の水収支を計算した結果，直接の計測が不可能な地下水は，流入量より漏出量が過多とわかった．御釜では融雪期後に著しい水位低下が見られるが，降水の影響を受けない結氷期間に一貫して水位低下が起こるためと判明した．水中ドローンによる探査は湖水の濁りにより思うような成果が得られなかったが，先行研究の調査で考えられたよりも複雑な湖底地形であることがわかった．また，湖底からの気泡上昇や熱水噴出といった活動の直接的証拠は発見されなかった．ヨウ素同位体比分析のための採水は調査のたびに行っているが，マシンタイムの制約から，分析はまだ行われていない．追加的に，放射性ラドンによる地下起源物質の寄与検出を試みたが，十分な放射線のカウント数が得られず，誤差が非常に大きい結果となった．
Analogue experiments of volcanic explosion focusing on pressure release processes

GOTO Akio, OBAYASHI Shigeru, FURUKAWA Takeshi, OGAWA Toshihiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Tohoku University

2008 - 2010

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When analyzing volcanic explosion we often suppose the instantaneous release of pressurized gas and ignore gas species. Our laboratory experiments have revealed that even if total released energy is the same the resultant phenomena differs depending on gas release rate and thermodynamic properties of volcanic gas. We also observed the activity of Villarrica volcano, Chile. We did not catch air wave accompanying explosions but detected stable monochromatic infrasound. Using this we determined the shape of the cavity in the vent.
Field experiments of MOVE for the construction of robot system for volcano observation

TANIGUCHI Hiromitsu, GOTO Akio, UEKI Sadato, NAGATANI Keisi, KANEKO Katsuya, NISHIMURA Takeshi, OSHIMA Hiromitsu, ICHIHARA Mie, SAIKI Kazuto

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2007 - 2009

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We are aiming at the development of the robotic system that can observe the volcano by wireless control in a near future. For that purpose, we developed MOVE (Mobile Observatory for Volcanic Explosions) based on Grant-in-Aid for Scientific Research on Priority Areas "Volcanic Explosion" that had ended in 2002 fiscal year. This MOVE is improved in the present study for the achievement of the robotic system. In addition, we tried to clarify various problems for development and the solutions based on the field experiment of MOVE. The vegetation and geographical barriers became the troubles when MOVE was used on an actual volcano, and the problem occurred in the wireless control. To avoid this, the base station vehicle was produced in the present study. The wireless machine and the extensible antenna, etc. were installed in the base station car. Next, we selected the volcanoes they were able to be applied actually. The selection was judged based on the possibility of volcanic eruption and the absence of trouble in wireless control. The trouble to the wireless was judged by the examination using the geographical software (KASHMIR) and the site investigation. As a result, two volcanoes (the Aso volcano and the Oshima volcano) were selected for the field experiment. Running and observation experiments in the field were performed twice (March and October, 2009) at these two volcanoes. In these experiments, the wireless control became possible by moving the base station at the points where the wireless control was impossible in the experiment before. As a result, the transport of MOVE from a point parting at about 2km to the summit crater succeeded by the wireless control at the Aso volcano and the Miharayama volcano. Moreover, at the Miharayama experiment, we exchanged the information with the robot researcher in a different field like the engineering system etc. and obtained useful information for the robotic system construction in the future. However, to use the robotic system for the progress in science and disaster prevention, it was clarified that a lot of problems were left such as an increase in the capital, the number of researchers and the construction of operation organization.
Joint research among Japan, Korea and China on the active history and magma of Baitoushan Volcano

TANIGUCHI Hiromitsu, KURITANI Takeshi, MIYAMOTO Tsuyoshi, NAGASE Toshirou, KANNO Hitoshi, GOTO Akio, NAKAGAWA Mitsuhiro, OKUNO Mituru, BAN Masao, MAENO Fukashi, SHIMANO Taketo, ITAYA Tetsumaru, YASUDA Yoshinori, UEKI Sadato, FURUHATA Toru, KOJIMA Yoshitaka

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A)

Institution: Tohoku University

2005 - 2008
火山爆発にともなう地表現象に対する新研究手法の開発と適用

谷口宏充, 今村文彦, 佐宗章弘, 後藤章夫, 山田功夫, 齋藤務, 大島弘光

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 特定領域研究

Institution: 東北大学

2002 - 2006

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火山探査移動観測ステーション:当初に掲げた‘2km離れた地点からの無線操縦と観測データの送受信'は実現していることが確認されているので、本年度は、実際の噴火観測への運用を確実にするため、1986年の大島三原山の噴火推移に即してシナリオを作成し観測演習を行った。登坂走行や観測上の問題点などを明らかにしつつ、演習としてはおおむね満足すべき成果を得、実用への目処をつけた。火山観測用ドップラーレーダ:今年度はシステムを構成するデータ取得、処理系のプログラムの修正と改良を実施した。実際の火山噴火を対象とした試験観測をおこなうことは出来なかったが、野外における実験観測を通して実用化への目途をつけた。ヘリコプター投下型GPS観測システム:2005年10月浅間山において取得したデータに予期しないデータの欠落があり、これが測位解析結果の良くない原因であることが分かった。そこでデータの欠落があり、短く切れているデータを捨てたうえで再度解析を行ったところ、かなり改善された。火山爆発模擬実験装置:クレータ形成について、高圧ガスの駆動力と砂の挙動の力学的マッチングによってその飛散形態が大きく異なる観測結果をモデル化した。高圧ガス容器内の圧力履歴は一次元準定常ガス放出モデルで再現できること、砂の運動とガスの放出がマッチングするとドーム状の飛散形態となり、運動量交換が最大になることなどがわかった。火山性爆風数値計算コード:爆発的噴火による爆風の発生と伝播、そして火砕サージの流下過程を模擬する計算コードを開発してきた。昨年度で実際の地形をも考慮した、火砕サージの3次元数値模擬計算コード開発を行い、本年度は有珠火山と桜島火山などの火山を対象に数値実験を繰り返し、現象の再現は成功している。火山性津波数値計算コード:喜界カルデラ津波に対し、崩壊モデルや火砕流突入モデルなどを検討し、津波規模の推定解析を行った。
Establishment of the scaling rule for explosive eruption and its application to the estimation of hazard distribution

TANIGUCHI Hiromitsu, MIYAMOTO Tsuyoshi, GOTO Akio, NISHIMURA Takeshi, OSHIMA Hiromitsu, HAYASHI Shintaro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: TOHOKU UNIVERSITY

2001 - 2002

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This research work intends to establish the scaling rule that relates the explosion energy and depth of volcanic explosion to the extension and strength of volcanic disaster such as volcanic blast wave, pyroclastic surge and ballistic fragment. For this purpose, we made some field explosion experiments under both of the conditions on the dry ground and in water. These two years we have concentrated on the underwater experiment for getting the understanding of submarine eruption. The main points of observation accompanied to the experiments are as follows : 1.Observation of underwater pressure waves using blast-sensor and underwater microphone 2.Observation of shock wave in the air using blast sensor and high-speed video recorder 3.Observations of water-dome and ballistic fragment usnig visible and infra-red video recorders 4.Simultaneous recording of eqrthquake, air wave and visible image of the explosion The weigh of explosives used (Kiri-dynamite) were ranged from 250g to 4000g, adn the scaled depth ranged from 0 to 2.15 m/g^1/3. Based on these experiments, weconvinced that the scaling rule for underwater volcanic eruption could be also establishd as in the case on dry ground.
マグマに含まれる水がマグマの粘性に及ぼす効果の実験的研究

後藤章夫

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

2000 - 2001

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マグマの粘性係数は水が入ると劇的に低下する。含水マグマの粘性測定は今までも行われているが、データ量は十分とは言い難く、また測定には大がかりな装置が必要だった。そこで本研究では、オートクレーブによって試料を水和させ、その粘性係数をガラス繊維引き伸ばし法で測定するという、簡便な方法を開発した。実験に用いた試料は十勝岳1988-89噴出物、雲仙第4ドーム溶岩、白滝村黒曜石(合成)の3種類で、それらを1600℃で溶融したのち、直径0.6mm前後の繊維状ガラス試料に加工した。それらを純水とともにオートクレーブに入れ、200〜500℃、0.2〜30MPaで12〜172時間保持した。その結果ある条件下では、中心まで水和したガラスを作ることに成功した。例えば白滝村黒曜石を500℃、1.2MPaで44時間保持した場合、0.42wt%の水を含んでいることが顕微赤外分光による分析で確認された。しかし試料表面には結晶化などの変質が見られたため、その影響を取り除くためフッ化水素酸に5分間浸けて変質部を除去し粘性測定に用いた。測定の結果、水の効果によると思われる著しい粘性低下が確認された。例えば上記黒曜石では800℃における粘性係数(Pa s)は対数スケールで9.34で、無水試料の粘性(11.48)に比べ2桁以上低かった。このように従来より簡便な方法で含水マグマの粘性を測定するシステムを構築することに成功し、今後データの大量生産が可能になると期待される。
Development of the measurement-system of volcanic shock wave both in the air and in the water

TANIGUCHI Hiromitsu, OHBA Tsukasa, NISHIMURA Takeshi, OSHIMA Hiromitsu, MIYAMOTO Tsuyoshi, GOTO Aiko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B).

Institution: Tohoku University

1998 - 2000

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Main purpose of this project is to make a system for volcanic blast wave measurement both in the air and in the water, and to determine the explosion energy and depth of explosive eruption. The ability of the system is as follows : 1. Sampling rate : 〜200 kHz 2. Number of data collection : ca. 10000 For making the system, field explosion experiment was needed. Using this chance, we have attempeted to establish the scaling rule which govern the relations among explosion energy, explosion depth and surface phenomenon of volcanic explosion such as the crater formation and ejection of ballistic fragment. On 31 March 2000, Usu volcano in Hokkaido, Japan, erupted after 22 years dormancy, and it was characterized by numerous numbers of small-scale phreatic explosion. We have attacked to determine the energy and the depth of Usu eruption based on the observations and the scaling rule. These results indicated that the experimental eqtuations obtained in the field experiment relating the explosion energy and depth to the explosion phenomenon explained well quantitatively the real phenomenon at Usu phreatic explosion. The representative explosion energy observed ranged from 10^10 J to l0^12 J, and the representative depth ranged from almost crater surface to about 30 m deep.
Physical properties, structure and destruction of magmatic silicate melt and their implication to the magmatic process

TANIGUCHI Hiromitsu, KUDOH Yasuhiro, OHTANI Eiji, FUJIMAKI Hirokazu, GOTO Akio

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (A).

Institution: Tohoku University

1998 - 2000

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The purpose of this research project are : 1. To make the system of measurement of physical properties of magmatic silicate melt both under 1 atm and high pressure, and both under high temperature and low temperature including liquid state, super-cooled liquid state and glassy state. 2. The physical properties we have planed to measure are viscosity coefficient, density and some related properties. 3. To understand the concrete mechanism of a magmatic process, we have also planned to determine the structure of related materials including glass and mineral, and to apply the determination of both explosion energy and the depth of explosive volcanism. Unfortunately, it took one and a half year to construct the system, we could not get enough data for the purpose, however, the followings are the main summary at the present : 1. The establishment of universal viscosity-equation which is applicable to wide temperature rage of magmatic silicate melt based on the WLF equation. This enable us to calculate the viscosity at around 1000 ℃. 2. We have presented a new model of mechanism of an earthquake generated by the destruction of magmatic silicate melt. 3. We have determined the viscosity and density of melts of albite and peridotite compositions for the understanding of a magma ocean. 4. We have determined the structure of hydrous ringwoodite. 5. We have suceeded in the determination of both explosion energy and explosion depth of the Usu 2000 phreatic explosions.

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Media Coverage 1

NHKニュース7，ニュースウオッチ9

2011/02/02

Type: TV or radio program

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新燃岳噴火で発生した空振に関するコメント

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溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明－その5：伊豆大島三原山溶岩流の特異性に着目して－

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伊豆大島では1950-1951年噴火及び1986年噴火で，山頂火口から溢流した溶岩流に対して，厚さや流速などから粘性係数が求められている（村内，1950；Minakami, 1951；白尾，1987）．その値は1950年が1.7×104 Pa s（1063℃）～3.3×106 Pa s（1048℃），1951年が5.6×102 Pa s（1125℃）～2.3×104 Pa s（1038℃），1986年が1.7×104 Pa s～1.2×107 Pa s（温度データなし）で，1950年はわずか15℃で2桁以上の変化がある，1950年の1048℃のほうが1951年の1038℃より2桁以上高粘性であるなど，不可解な点がある．これまで伊豆大島溶岩の粘性係数は系統立てた定量的な研究がなされていなかった．そこで平成28年度の一般共同研究で，一軸圧縮による粘性係数測定を開始した．計画では，組織の違いやひずみ速度依存性にも着目し，噴火年が異なる溶岩流でその流動特性を明らかにすることを目的とした．そのために噴火年や表面形態の異なる溶岩流から試料を採取し，1986年LC溶岩から測定を開始した．すると，1070℃付近までは有意な流動を示さなかったのが，1090℃を越えると急激に流動化するという，実験前には予想していなかった現象が起こった．その変化があまりに急激で，適切な測定条件を現在も模索中のため，本申請時点でその流動特性を十分明らかにするには至っていない．この急変の原因はまだ明らかでないが，同様の現象が伊豆大島溶岩の動的特性を強く規定し，上で述べた不可解な粘性係数にも深く関係していることも考えられる．そこで採取済の伊豆大島溶岩試料を用いて，平成29年度も引き続き粘性係数測定を行い，噴火年や溶岩流の表面形態による流動特性の違いを明らかにする．また熱分析や，実験前後で試料の薄片観察も行い，温度による流動特性急変の原因を探る．我々は平成25年度から27年度まで，共同研究で雲仙普賢岳平成溶岩を対象とした粘性係数測定を行ってきた．この溶岩では観測から求められた粘性係数が，温度と化学組成から予想される値より数桁低く，なぜ平成溶岩がそれほどに“流れやすかったのか”という疑問があった．測定の結果，普賢岳の溶岩はほとんど流動性を失っていたことが改めて示され，流動よりむしろ脆性変形や底面の滑りが運動の主体だったという考えに至った．そこで観測からの見積もりの妥当性を疑い，当時の連続写真とビデオを入手して再解析したところ，溶岩が剛体的に斜面を滑っていたことが確認された（火山学会2016年秋季大会で報告）．伊豆大島1951年溶岩についても，Minakami (1951)は観測から求めた粘性係数は室内実験で測定された値の数十分の一の低さであることを指摘している．Minakami (1951)は揮
溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明－その4：伊豆大島三原山溶岩流－

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伊豆大島では地下のマグマ蓄積によると思われる山体膨張が続き，次の噴火が近づきつつあると見られている．伊豆大島の溶岩は玄武岩質で，溶岩流の発生が活動の特徴の一つである．溶岩流の粘性係数はその運動を支配し，シミュレーションにも欠かせず，防災の観点からもその値を知ることは重要である．伊豆大島では1950-1951年噴火及び1986年噴火で，山頂火口から溢流した溶岩流に対して，厚さや流速などから粘性係数が求められている（村内，1950；Minakami, 1951；白尾，1987）．その値は1950年が1.7×104 Pa s（1063℃）～3.3×106 Pa s（1048℃），1951年が5.6×102 Pa s（1125℃）～2.3×104 Pa s（1038℃），1986年が1.7×104 Pa s～1.2×107 Pa s（温度データなし）で，1950年はわずか15℃で2桁以上の変化がある，1950年の1048℃のほうが1951年の1038℃より2桁以上高粘性であるなど，不可解な点がある．またMinakami (1951)は，観測から求めた粘性係数より室内実験で測定された値のほうが数十倍高いことを指摘した．Minakami (1951)は揮発性物質の量の違いでこの差が生じたと推測したが，結晶量の違いや，ひずみ速度依存性の違いの影響も考えられる．先の不可解な点を含め，これまで伊豆大島溶岩の粘性係数には，系統立てた定量的な研究がなされてこなかった．そこで本研究は伊豆大島の噴火年が異なる溶岩流から試料を採取し，流下時に近い温度での粘性係数測定を行い，組織の違いやひずみ速度依存性にも着目し，その流動特性を明らかにする．私たちは平成25年度から27年度まで，雲仙普賢岳平成溶岩を対象とした粘性係数測定を行ってきた．この溶岩でも観測から求められた粘性係数が予想される値より数桁低く，なぜ平成溶岩がそれほどに“流れやすかったのか”という疑問があった．測定の結果，普賢岳の溶岩は噴出時にはほとんど流動性を失っていたことが示され，流動よりむしろ脆性変形や底面の滑りが運動の主体だったという考えに至り，現在，観測データでの検証を進めている．デイサイト質の雲仙平成溶岩と玄武岩質の伊豆大島溶岩でどのような共通性・相違性があるか，興味が持たれる．
溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明－その3：組織変化に着目して－

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観測から求められた雲仙普賢岳平成溶岩ローブの粘性係数は，実験室内で測定された石基ガラス組成のメルトの粘性係数よりも2桁ほど低い．なぜ平成溶岩がそれほどに“流れやすかったのか”という疑問に答えるため，平成25，26年度の一般共同研究で，一軸圧縮による溶岩試料の粘性係数測定を行ってきた．その結果，測定された粘性係数は石基メルトに結晶による粘性増加を考慮した値と調和的で，それより数桁低い観測値は溶岩の流動では説明できないことがはっきりした．実験で得られたような高粘性では，ローブ底部に生じるひずみ速度で流動による脆性破壊が起こりうるので，そのような破壊と，破壊面での滑りが溶岩ローブの運動の主要因と考えている．その痕跡を探すため，本申請直後の11月初めに，福岡で火山学会が開催される機会を利用し，それに引き続いて雲仙普賢岳でローブ溶岩の調査を予定している．これまでの実験で，粘性係数の数十時間にわたる増加（一定応力下でのひずみ速度の減少）が見られ，それは特に，試験力が低い時や，試料の空隙率が高い時に顕著であった．この原因が不明だったが，空隙がつぶれて緻密化していくプロセスを見ているらしいことが最近わかってきた．しかしここで新たな疑問が生じる．試料は天然において，実験より遙かに長時間の変形を被っており，応力に対して十分平衡に達しているはずである．それがなぜ改めてつぶれるのか？一つの仮説として，そのように空隙を持つ試料は十分な応力を受けなかったローブの比較的上部に由来し，さらに，流動にはほとんど寄与していなかったことが考えられる．これまでは実験試料に転石を用いていたが，ローブの部位がわかった試料を使い，内部組織とも結びつけて考える必要がある．11月の調査で産状のはっきりした試料を採取し，それを実験に用いることで，ローブ溶岩の運動を支配する要因を明らかにする．
溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明－その2－

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雲仙普賢岳平成溶岩ローブの粘性係数は，観測から1010～1010.5 Pa sと求められている．これに対し，石基ガラス組成のメルトの粘性係数は，実測で800℃のとき1012.5 Pa sと観測値より高い．水による粘性低下を考慮しても，結晶による粘性増加はそれを上回り，観測された低い粘性係数を説明できない（Goto, 1999）．同様のことは伊豆大島三原山の1951年溶岩流でも報告されている（Minakami, 1951）．この問題を解決するため，平成25年度の一般共同研究で，一軸圧縮による普賢岳平成溶岩試料の粘性係数測定を行っている．これまでの実験で，溶岩試料の粘性係数は確かに観測値より高いことが確かめられ，溶岩ローブはニュートン流動以外のメカニズムで移動していたことが強く示唆された．しかしながら，同じ岩塊からの試料では結果に再現性があるにもかかわらず，全岩組成や岩石組織がほぼ同じ二つの岩塊で実験値が異なることや，粘性係数が時間に対して増加し，特に低応力では10時間までのランタイム内で一定値に収束しないなど，当初予想しなかった新たな問題が現れている．そのため，平成26年度も引き続いての申請を行う．安田准教授が代表を務める特定共同研究(B)「顕微FTIR反射分光法の応用と高度化:含水量データ10倍増計画」にも参加予定なので，この中で粘性測定前後の試料の含水量を測定し，脱水が粘性増加の原因であるかの検証や，平成溶岩と新焼溶岩の挙動の違い（前者は火砕流を発生させ，後者は斜面を溶岩流として流れ下った）と水との関連も追求する．また，サンプリングを行いながら測定するには至っていない，伊豆大島溶岩についても測定を行い，近い将来に予想される噴火に際し，流下範囲の予測などに有用なデータを取得する．
蔵王火山の現地調査

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2011年の東北地方太平洋沖地震で蔵王山の活動が活発化する可能性を鑑み，現地での噴気温観測，湧水分析，御釜の湖水分析及び水深測定を行う．
溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明

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溶岩流の粘性係数は，地形とともにその流動を支配し，シミュレーションにも欠かせない．溶岩の粘性係数は，流動性を持つ溶融部の粘性係数と，含まれる結晶の量や形で決まると考えられるが，それらから推定される値と，溶岩流の厚さや流速から求められる値とは一致しないことが多い．雲仙普賢岳の平成溶岩の場合，観測から1010～1010.5 Pa sと求められているが，石基ガラス組成のメルトの粘性係数は800℃のとき1012.5 Pa sと観測値より高く，水による低下を考慮しても，結晶の効果によりさらに高い値が予想される（Goto, 1999）．これは，溶岩流の運動にはニュートン流動以外のメカニズムが関与していることを示唆する．同様のことは伊豆大島三原山の1951年溶岩流でも報告されている（Minakami, 1951）．雲仙普賢岳に関しては，平成溶岩と約200年前の新焼溶岩は岩石学的にほぼ同一とされているにも関わらず，前者は崩落型火砕流を発生させたのに対し，後者はそれなしに斜面を溶岩流として流れ下ったという問題もある．これは後者が高温で粘性が低かったためと説明されているが，流動特性を実測で比較したわけではなく，推測の域を出ない．本研究では，これら溶岩の粘性係数を実際に測定し，その流動特性を明らかにすることで，溶岩流の流動機構を考察する．
溶岩流試料の室内実験による粘性係数測定と，野外観測値との比較に基づく，溶岩流流動機構の解明

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溶岩流の粘性係数は，地形とともにその流動を支配し，シミュレーションにも欠かせない．溶岩の粘性係数は，流動性を持つ溶融部の粘性係数と，含まれる結晶の量や形で決まると考えられるが，それらから推定される値と，溶岩流の厚さや流速から求められる値とは一致しないことが多い．雲仙普賢岳の平成溶岩の場合，観測から10¹⁰～10^10.5 Pa sと求められているが，石基ガラス組成のメルトの粘性係数は800℃のとき10^12.5 Pa sと観測値より高く，水による低下を考慮しても，結晶の効果によりさらに高いが予想される（Goto, 1999）．これは，溶岩流の運動にはニュートン流動以外のメカニズムが関与していることを示唆する．同様のことは伊豆大島三原山の1951年溶岩流でも報告されている（Minakami, 1951）．雲仙普賢岳に関しては，平成溶岩と約200年前の新焼溶岩は岩石学的にほぼ同一とされているにも関わらず，前者は崩落型火砕流を発生させたのに対し，後者はそれなしに斜面を溶岩流として流れ下ったという問題もある．これは後者が高温で粘性が低かったためと説明されているが，流動特性を実測で比較したわけではなく，推測の域を出ない．本研究では，これら溶岩の粘性係数を実際に測定し，その流動特性を明らかにすることで，溶岩流の流動機構を考察する．
映像・空振高速度同時記録システム構築と，火山観測への適用

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高速度カメラと高周波数まで測定可能なマイクロフォンを時間同期させた高速度収録システムを構築し，それを用いた観測によって，今まで認識されていなかったミリ秒スケールでの火山現象の検出を試みる．
イタリア・ストロンボリ火山の噴火データ取得と空振観測

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ストロンボリ火山に赴き，前年度のCOE研究費で構築した野外高速度収録システムにより空振観測を行い，彼が行っている地震・映像観測のデータとセットにして解析を行う．
高圧ガスを用いた火山爆発模擬実験－特にガスと飛散物の相互作用に着目して－

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流体科学研究所との連携のもと，高圧ガスの噴出で砂を飛散させる火山爆発模擬実験を発展させる．飛散物の粒径を変えるなどして，ガスと飛散物の相互作用を捉えることを目指した．またこの実験で用いられる技術を応用して，実際の火山で圧力波を機動的に観測するためのシステムを構築した．
火山噴火の模擬としての間欠泉観測

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火山噴火の模擬として間欠泉で見られる変動を定量的に計測し，そのメカニズムと地球物理学的な観測量への関与を明らかにすることを目指した．
火山熱流体シミュレーションと環境影響予測手法の開発

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溶岩流シミュレーションコードの開発

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